Greenhouse gas impacts of ethanol from Iowa corn: Life cycle assessment versus system wide approach

International Nuclear Information System (INIS)

Feng, Hongli; Rubin, Ofir D.; Babcock, Bruce A.

2010-01-01

Life cycle assessment (LCA) is the standard approach used to evaluate the greenhouse gas (GHG) benefits of biofuels. However, the need for the appropriate use of LCA in policy contexts is highlighted by recent findings that corn-based ethanol may actually increase GHG emissions. This is in contrary to most existing LCA results. LCA estimates can vary across studies due to heterogeneities in inputs and production technology. Whether marginal or average impacts are considered can matter as well. Most important of all, LCA is product-centered. The determination of the impact of biofuels expansion requires a system wide approach (SWA) that accounts for impacts on all affected products and processes. This paper presents both LCA and SWA for ethanol based on Iowa corn. LCA was conducted in several different ways. Growing corn in rotation with soybean generates 35% less GHG emissions than growing corn after corn. Based on average corn production, ethanol's GHG benefits were lower in 2007 than in 2006 because of an increase in continuous corn in 2007. When only additional corn was considered, ethanol emitted about 22% less GHGs than gasoline. SWA was applied to two simple cases. Using 2006 as a baseline and 2007 as a scenario, corn ethanol's benefits were about 20% of the emissions of gasoline. If geographical limits are expanded beyond Iowa, then corn ethanol could generate more GHG emissions than gasoline. These results highlight the importance of boundary definition for both LCA and SWA.

Greenhouse gas impacts of ethanol from Iowa corn: Life cycle assessment versus system wide approach

Energy Technology Data Exchange (ETDEWEB)

Feng, Hongli [Department of Economics, 377 Heady Hall, Iowa State University, Ames, IA 50011-1070 (United States); Rubin, Ofir D. [Department of Economics, 573 Heady Hall, Iowa State University, Ames, IA 50011-1070 (United States); Babcock, Bruce A. [Center for Agricultural and Rural Development (CARD), Iowa State University, Ames, IA 50011-1070 (United States); Department of Economics, 578F Heady Hall, Iowa State University, Ames, IA 50011-1070 (United States)

2010-06-15

Life cycle assessment (LCA) is the standard approach used to evaluate the greenhouse gas (GHG) benefits of biofuels. However, the need for the appropriate use of LCA in policy contexts is highlighted by recent findings that corn-based ethanol may actually increase GHG emissions. This is in contrary to most existing LCA results. LCA estimates can vary across studies due to heterogeneities in inputs and production technology. Whether marginal or average impacts are considered can matter as well. Most important of all, LCA is product-centered. The determination of the impact of biofuels expansion requires a system wide approach (SWA) that accounts for impacts on all affected products and processes. This paper presents both LCA and SWA for ethanol based on Iowa corn. LCA was conducted in several different ways. Growing corn in rotation with soybean generates 35% less GHG emissions than growing corn after corn. Based on average corn production, ethanol's GHG benefits were lower in 2007 than in 2006 because of an increase in continuous corn in 2007. When only additional corn was considered, ethanol emitted about 22% less GHGs than gasoline. SWA was applied to two simple cases. Using 2006 as a baseline and 2007 as a scenario, corn ethanol's benefits were about 20% of the emissions of gasoline. If geographical limits are expanded beyond Iowa, then corn ethanol could generate more GHG emissions than gasoline. These results highlight the importance of boundary definition for both LCA and SWA. (author)

Kinetic modeling of simultaneous saccharification and fermentation of corn starch for ethanol production.

Science.gov (United States)

Białas, Wojciech; Czerniak, Adrian; Szymanowska-Powałowska, Daria

2014-01-01

Fuel ethanol production, using a simultaneous saccharification and fermentation process (SSF) of native starch from corn flour, has been performed using Saccharomyces cerevisiae and a granular starch hydrolyzing enzyme. The quantitative effects of mash concentration, enzyme dose and pH were investigated with the use of a Box-Wilson central composite design protocol. Proceeding from results obtained in optimal fermentation conditions, a kinetics model relating the utilization rates of starch and glucose as well as the production rates of ethanol and biomass was tested. Moreover, scanning electron microscopy (SEM) was applied to investigate corn starch granule surface after the SFF process. A maximum ethanol concentration of 110.36 g/l was obtained for native corn starch using a mash concentration of 25%, which resulted in ethanol yield of 85.71%. The optimal conditions for the above yield were found with an enzyme dose of 2.05 ml/kg and pH of 5.0. These results indicate that by using a central composite design, it is possible to determine optimal values of the fermentation parameters for maximum ethanol production. The investigated kinetics model can be used to describe SSF process conducted with granular starch hydrolyzing enzymes. The SEM micrographs reveal randomly distributed holes on the surface of granules.

Growing ethanol sector drives corn supply chain shift for the last decade

Science.gov (United States)

Kim, T.; Schmitt, J.; Brauman, K. A.; Smith, T. M.; Suh, K.

2017-12-01

The US is the largest producer in the world, 89% of corn production uses in domestic demands in 2012. Carbon emission and irrigated water usage in the corn farming stage are hot-spot in the meat production sectors, comprise 37% of all US corn demand. The annual capacity of the ethanol sector increases from 6.5 billion gallons to 15.3 billion gallons for the last decade. The growth of corn demand in ethanol sector makes corn supply chain shift. Most of the ethanol plants located in the Mid-west where is the top 12 corn producing states. Therefore animal feeds take more supply from the other states. The purpose of this study is to estimate environmental impacts and water scarcity associated embedded corn by the temporal and spatial corn supply chain model based on a cost minimization. We use publicly available county-level data on corn production, feed demands, aggregative carbon emission and irrigated water usage in farming state, and a water depletion index as a metric for determining water scarcity. The water stressed counties produce 23.3% of US total corn production in 2012, and the irrigated corn is 14.2%. We simulated the corn supply chain using linear programming and developed the web-based visualization tools called FoodS3 (Food Systems Supply-chain Sustainability tool, http://foods3.org).

Greenhouse gases in the corn-to-fuel ethanol pathway.

Energy Technology Data Exchange (ETDEWEB)

Wang, M. Q.

1998-06-18

Argonne National Laboratory (ANL) has applied its Greenhouse gas, Regulated Emissions and Energy in Transportation (GREET) full-fuel-cycle analysis model to examine greenhouse gas (GHG) emissions of corn-feedstock ethanol, given present and near-future production technology and practice. On the basis of updated information appropriate to corn farming and processing operations in the four principal corn- and ethanol-producing states (Illinois, Iowa, Minnesota, and Nebraska), the model was used to estimate energy requirements and GHG emissions of corn farming; the manufacture, transportation to farms, and field application of fertilizer and pesticide; transportation of harvested corn to ethanol plants; nitrous oxide emissions from cultivated cornfields; ethanol production in current average and future technology wet and dry mills; and operation of cars and light trucks using ethanol fuels. For all cases examined on the basis of mass emissions per travel mile, the corn-to-ethanol fuel cycle for Midwest-produced ethanol used in both E85 and E10 blends with gasoline outperforms conventional (current) and reformulated (future) gasoline with respect to energy use and GHG production. Also, GHG reductions (but not energy use) appear surprisingly sensitive to the value chosen for combined soil and leached N-fertilizer conversion to nitrous oxide. Co-product energy-use attribution remains the single key factor in estimating ethanol's relative benefits because this value can range from 0 to 50%, depending on the attribution method chosen.

Greenhouse gases in the corn-to-fuel ethanol pathway

International Nuclear Information System (INIS)

Wang, M. Q.

1998-01-01

Argonne National Laboratory (ANL) has applied its Greenhouse gas, Regulated Emissions and Energy in Transportation (GREET) full-fuel-cycle analysis model to examine greenhouse gas (GHG) emissions of corn-feedstock ethanol, given present and near-future production technology and practice. On the basis of updated information appropriate to corn farming and processing operations in the four principal corn- and ethanol-producing states (Illinois, Iowa, Minnesota, and Nebraska), the model was used to estimate energy requirements and GHG emissions of corn farming; the manufacture, transportation to farms, and field application of fertilizer and pesticide; transportation of harvested corn to ethanol plants; nitrous oxide emissions from cultivated cornfields; ethanol production in current average and future technology wet and dry mills; and operation of cars and light trucks using ethanol fuels. For all cases examined on the basis of mass emissions per travel mile, the corn-to-ethanol fuel cycle for Midwest-produced ethanol used in both E85 and E10 blends with gasoline outperforms conventional (current) and reformulated (future) gasoline with respect to energy use and GHG production. Also, GHG reductions (but not energy use) appear surprisingly sensitive to the value chosen for combined soil and leached N-fertilizer conversion to nitrous oxide. Co-product energy-use attribution remains the single key factor in estimating ethanol's relative benefits because this value can range from 0 to 50%, depending on the attribution method chosen

Possible effects of the Worldwide production of ethanol in two of the main countries that imports corn. South Korea and Mexico

Directory of Open Access Journals (Sweden)

Saúl Martínez González

2010-01-01

Full Text Available South Korea is the second largest importer of corn and Mexico is the third. Although the corn has its origin in this country, since 1994 Mexico has become one of the major importers in the world. This essay examines the possible economic implications for Mexico and Korea for the increased production of ethanol from corn. The analysis parts of the close relationship of three interconnected problems, which are at the root of the current energy crisis: global warming, oil crisis and biofuel production. This is causing a global food crisis. The production of ethanol from corn is emerging as an alternative that may address global warming and attacking the alleged shortage of oil, which has resulted in rising prices. The point in discussion is what are the possible effects of policies to induce the production of biofuels (ethanol on the main importers of corn. That’s why the current status of the ethanol industry is analyzed, whose main protagonists on the world stage are the United States and Brazil. Then we made a brief analysis of the market of corn. Finally, based on the foregoing, we reflect on the possible implications it might have on the development of food production of etanol.

Possibilities of utilization of co-products from corn grain ethanol and starch production

Directory of Open Access Journals (Sweden)

Semenčenko Valentina V.

2013-01-01

Full Text Available In recent decades, the expansion of alternative fuels production from crops traditionally used for food and animal feed has led to significant changes in the field of energy production, agriculture and food industry. Starch and sugar feedstocks for ethanol production (corn, wheat, sugar beet, sugar cane, etc. require increasing arable land to meet market demands for the biofuel production. Although intensive studies are being carried out in order to identify improved and more cost-effective methods for the utilization of lignocellulosic and communal waste in the production of alcohol fuel, the possibility of using dry distillers’ grains with solubles (DDGS, by-product of bioethanol production from corn and wheat as well as alcoholic beverages industry, is now in focus. Application of DDGS in livestock and poultry diets in concentrations greater than traditional could positively affect the economic viability of this biofuel production, but also stabilize the current imbalance in the food and animal feed market. However, DDGS feedstuff should not be treated as a perfect substitute for corn because the complexity of ration formulation determined at the farm or feedlot level is driven by energy and protein and other nutrient requirements, as well as their relative costs in the ration. Nevertheless, processing of corn by wet milling provides a multitude of co-products suitable for feedstuffs, food industry, pharmaceuticals, chemistry etc. Some of the most important wet milling co-products that have their use in feedstuffs are corn gluten feed and corn gluten meal. The use of DDGS as a substitute for traditional feed could prevent indirect land-use changes associated with biofuel production, and therefore preserve the environmental destruction by saving the forests and permanent pastures. The use of distiller’s grains can be beneficial to biofuel growth as this is an additional, the second largest, source of income accounting of 10-20% total

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

Science.gov (United States)

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.

Feasibility study for co-locating and integrating ethanol production plants from corn starch and lignocellulosic feedstocks

Energy Technology Data Exchange (ETDEWEB)

Wallace, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ibsen, Kelly [National Renewable Energy Lab. (NREL), Golden, CO (United States); McAloon, Andrew [U.S. Department of Agriculture, Washington, D.C. (United States); Yee, Winnie [U.S. Department of Agriculture, Washington, D.C. (United States)

2005-01-01

Analysis of the feasibility of co-locating corn-grain-to-ethanol and lignocellulosic ethanol plants and potential savings from combining utilities, ethanol purification, product processing, and fermentation.

Utilizing protein-lean coproducts from corn containing recombinant pharmaceutical proteins for ethanol production.

Science.gov (United States)

Paraman, Ilankovan; Moeller, Lorena; Scott, M Paul; Wang, Kan; Glatz, Charles E; Johnson, Lawrence A

2010-10-13

Protein-lean fractions of corn (maize) containing recombinant (r) pharmaceutical proteins were evaluated as a potential feedstock to produce fuel ethanol. The levels of residual r-proteins in the coproduct, distillers dry grains with solubles (DDGS), were determined. Transgenic corn lines containing recombinant green fluorescence protein (r-GFP) and a recombinant subunit vaccine of Escherichia coli enterotoxin (r-LTB), primarily expressed in endosperm, and another two corn lines containing recombinant human collagen (r-CIα1) and r-GFP, primarily expressed in germ, were used as model systems. The kernels were either ground and used for fermentation or dry fractionated to recover germ-rich fractions prior to grinding for fermentation. The finished beers of whole ground kernels and r-protein-spent endosperm solids contained 127-139 and 138-155 g/L ethanol concentrations, respectively. The ethanol levels did not differ among transgenic and normal corn feedstocks, indicating the residual r-proteins did not negatively affect ethanol production. r-Protein extraction and germ removal also did not negatively affect fermentation of the remaining mass. Most r-proteins were inactivated during the mashing process used to prepare corn for fermentation. No functionally active r-GFP or r-LTB proteins were found after fermentation of the r-protein-spent solids; however, a small quantity of residual r-CIα1 was detected in DDGS, indicating that the safety of DDGS produced from transgenic grain for r-protein production needs to be evaluated for each event. Protease treatment during fermentation completely hydrolyzed the residual r-CIα1, and no residual r-proteins were detectable in DDGS.

Ethanol production using Saccharomyces cerevisiae cells immobilised on corn stem ground tissue

Directory of Open Access Journals (Sweden)

Vučurović Vesna M.

2009-01-01

Full Text Available Cell immobilisation in alcoholic fermentation has been extensively studied during the past few decades because of its technical and economical advantages over those of free cell systems. A biocatalyst was prepared by immobilising a commercial Saccharomyces cerevisiae strain (baker yeast on corn stem ground tissue for use in alcoholic fermentation. For this purpose, the yeast cells were submitted to the batch tests 'in situ' adsorption onto pieces of the corn stem ground tissue. Cells immobilisation was analysed by optical microscopy. It was determined that the addition of the corn stem ground tissue led to an increase of the pH value, total dissolved salts content, and sugar content in fermentation medium. The addition of 5 and 10g of the corn stem ground tissue per liter of medium, increased ethanol yield, decreased amount of residual sugar and the cells immobilisation was effective. Corn stem is one of the abundant, available, inexpensive, stable, reusable, nontoxic celulosic biomaterial with high porosity, which facilitates the transmission of substrates and products between carrier and medium. The prepared immobilised biocatalyst showed higher fermentation activity than free cells. The results indicate that corn stem might be an interesting support for yeast cell immobilisation, and also a cheap alternative recourse of mineral components with possibility of application for improving ethanol productivities.

Sequential saccharification of corn fiber and ethanol production by the brown rot fungus Gloeophyllum trabeum.

Science.gov (United States)

Rasmussen, M L; Shrestha, P; Khanal, S K; Pometto, A L; Hans van Leeuwen, J

2010-05-01

Degradation of lignocellulosic biomass to sugars through a purely biological process is a key to sustainable biofuel production. Hydrolysis of the corn wet-milling co-product-corn fiber-to simple sugars by the brown rot fungus Gloeophyllum trabeum was studied in suspended-culture and solid-state fermentations. Suspended-culture experiments were not effective in producing harvestable sugars from the corn fiber. The fungus consumed sugars released by fungal extracellular enzymes. Solid-state fermentation demonstrated up to 40% fiber degradation within 9days. Enzyme activity assays on solid-state fermentation filtrates confirmed the involvement of starch- and cellulose-degrading enzymes. To reduce fungal consumption of sugars and to accelerate enzyme activity, 2- and 3-d solid-state fermentation biomasses (fiber and fungus) were submerged in buffer and incubated at 37 degrees C without shaking. This anaerobic incubation converted up to almost 11% of the corn fiber into harvestable reducing sugars. Sugars released by G. trabeum were fermented to a maximum yield of 3.3g ethanol/100g fiber. This is the first report, to our knowledge, of G. trabeum fermenting sugar to ethanol. The addition of Saccharomyces cerevisiae as a co-culture led to more rapid fermentation to a maximum yield of 4.0g ethanol/100g fiber. The findings demonstrate the potential for this simple fungal process, requiring no pretreatment of the corn fiber, to produce more ethanol by hydrolyzing and fermenting carbohydrates in this lignocellulosic co-product. Copyright 2010 Elsevier Ltd. All rights reserved.

Ethanol production from concentrated food waste hydrolysates with yeast cells immobilized on corn stalk

Energy Technology Data Exchange (ETDEWEB)

Yan, Shoubao [Huainan Normal Univ., Anhui (China). School of Life Science; Chen, Xiangsong; Wu, Jingyong; Wang, Pingchao [Chinese Academy of Sciences, Hefei (China). Key Lab. of Ion Beam Bio-engineering of Inst. of Plasma Physics

2012-05-15

The aim of the present study was to examine ethanol production from concentrated food waste hydrolysates using whole cells of S. cerevisiae immobilized on corn stalks. In order to improve cell immobilization efficiency, biological modification of the carrier was carried out by cellulase hydrolysis. The results show that proper modification of the carrier with cellulase hydrolysis was suitable for cell immobilization. The mechanism proposed, cellulase hydrolysis, not only increased the immobilized cell concentration, but also disrupted the sleek surface to become rough and porous, which enhanced ethanol production. In batch fermentation with an initial reducing sugar concentration of 202.64 {+-} 1.86 g/l, an optimal ethanol concentration of 87.91 {+-} 1.98 g/l was obtained using a modified corn stalk-immobilized cell system. The ethanol concentration produced by the immobilized cells was 6.9% higher than that produced by the free cells. Ethanol production in the 14th cycle repeated batch fermentation demonstrated the enhanced stability of the immobilized yeast cells. Under continuous fermentation in an immobilized cell reactor, the maximum ethanol concentration of 84.85 g/l, and the highest ethanol yield of 0.43 g/g (of reducing sugar) were achieved at hydraulic retention time (HRT) of 3.10 h, whereas the maximum volumetric ethanol productivity of 43.54 g/l/h was observed at a HRT of 1.55 h. (orig.)

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

Science.gov (United States)

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.

Market-oriented ethanol and corn-trade policies can reduce climate-induced US corn price volatility

International Nuclear Information System (INIS)

Verma, Monika; Diffenbaugh, Noah; Hertel, Thomas

2014-01-01

Agriculture is closely affected by climate. Over the past decade, biofuels have emerged as another important factor shaping the agricultural sector. We ask whether the presence of the US ethanol sector can play a role in moderating increases in US corn price variability, projected to occur in response to near-term global warming. Our findings suggest that the answer to this question depends heavily on the underlying forces shaping the ethanol industry. If mandate-driven, there is little doubt that the presence of the corn-ethanol sector will exacerbate price volatility. However, if market-driven, then the emergence of the corn-ethanol sector can be a double-edged sword for corn price volatility, possibly cushioning the impact of increased climate driven supply volatility, but also inheriting volatility from the newly integrated energy markets via crude oil price fluctuations. We find that empirically the former effect dominates, reducing price volatility by 27%. In contrast, mandates on ethanol production increase future price volatility by 54% in under future climate after 2020. We also consider the potential for liberalized international corn trade to cushion corn price volatility in the US. Our results suggest that allowing corn to move freely internationally serves to reduce the impact of near-term climate change on US corn price volatility by 8%. (letter)

Market-oriented ethanol and corn-trade policies can reduce climate-induced US corn price volatility

Science.gov (United States)

Verma, Monika; Hertel, Thomas; Diffenbaugh, Noah

2014-05-01

Agriculture is closely affected by climate. Over the past decade, biofuels have emerged as another important factor shaping the agricultural sector. We ask whether the presence of the US ethanol sector can play a role in moderating increases in US corn price variability, projected to occur in response to near-term global warming. Our findings suggest that the answer to this question depends heavily on the underlying forces shaping the ethanol industry. If mandate-driven, there is little doubt that the presence of the corn-ethanol sector will exacerbate price volatility. However, if market-driven, then the emergence of the corn-ethanol sector can be a double-edged sword for corn price volatility, possibly cushioning the impact of increased climate driven supply volatility, but also inheriting volatility from the newly integrated energy markets via crude oil price fluctuations. We find that empirically the former effect dominates, reducing price volatility by 27%. In contrast, mandates on ethanol production increase future price volatility by 54% in under future climate after 2020. We also consider the potential for liberalized international corn trade to cushion corn price volatility in the US. Our results suggest that allowing corn to move freely internationally serves to reduce the impact of near-term climate change on US corn price volatility by 8%.

Explaining the reductions in US corn ethanol processing costs: Testing competing hypotheses

International Nuclear Information System (INIS)

Chen Xiaoguang; Khanna, Madhu

2012-01-01

The processing costs of US corn ethanol have declined by 45% since 1983 as production volumes have increased seventeen-fold. We investigate the role of various factors that could explain this, including economies of scale, cumulative experience, induced innovation in response to rising input prices, an autonomous technological change, and trade induced competition from imported ethanol. Using data on dry-mill ethanol processing costs over the 1983–2005 period, we find evidence to show that US corn ethanol production exhibited decreasing returns to scale, that learning by doing played an important role in reducing these processing costs with a learning rate of 0.25, and that sugarcane ethanol imports contributed to making the corn ethanol industry more competitive. Other factors such as the rising prices of energy and labor did induce lower processing costs, but the effect is not statistically significant. The inclusion of these competing explanations for the reduction in processing costs of US corn ethanol lead to a significantly higher learning rate than otherwise, and this learning rate is found to be robust across specifications. - Highlights: ► We investigate the role of various factors that could explain the reduction in US corn ethanol processing costs over the period 1983–2005. ► We find that US corn ethanol production exhibited decreasing returns to scale. ► Learning by doing played an important role in reducing these costs with a learning rate of 0.25. ► Sugarcane ethanol imports contributed to making the corn ethanol industry more competitive. ► Rising prices of energy and labor did induce lower processing costs, but the effect is not statistically significant.

Feasibility Study for Co-Locating and Integrating Ethanol Production Plants from Corn Starch and Lignocellulosic Feedstocks (Revised)

Energy Technology Data Exchange (ETDEWEB)

Wallace, R.; Ibsen, K.; McAloon, A.; Yee, W.

2005-01-01

Analysis of the feasibility of co-locating corn-grain-to-ethanol and lignocellulosic ethanol plants and potential savings from combining utilities, ethanol purification, product processing, and fermentation. Although none of the scenarios identified could produce ethanol at lower cost than a straight grain ethanol plant, several were lower cost than a straight cellulosic ethanol plant.

Fuel-Cycle Fossil Energy Use and Greenhouse Gas Emissions of Fuel Ethanol Produced from U.S. Midwest Corn

Energy Technology Data Exchange (ETDEWEB)

Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States); Saricks, Christoper [Argonne National Lab. (ANL), Argonne, IL (United States); Wu, May [Argonne National Lab. (ANL), Argonne, IL (United States)

1997-12-19

This study addresses two issues: (1) data and information essential to an informed choice about the corn-to-ethanol cycle are in need of updating, thanks to scientific and technological advances in both corn farming and ethanol production; and (2) generalized national estimates of energy intensities and greenhouse gas (GHG) production are of less relevance than estimates based specifically on activities and practices in the principal domestic corn production and milling region -- the upper Midwest.

Enzymatic digestibility and ethanol fermentability of AFEX-treated starch-rich lignocellulosics such as corn silage and whole corn plant

Directory of Open Access Journals (Sweden)

Thelen Kurt D

2010-06-01

Full Text Available Abstract Background Corn grain is an important renewable source for bioethanol production in the USA. Corn ethanol is currently produced by steam liquefaction of starch-rich grains followed by enzymatic saccharification and fermentation. Corn stover (the non-grain parts of the plant is a potential feedstock to produce cellulosic ethanol in second-generation biorefineries. At present, corn grain is harvested by removing the grain from the living plant while leaving the stover behind on the field. Alternatively, whole corn plants can be harvested to cohydrolyze both starch and cellulose after a suitable thermochemical pretreatment to produce fermentable monomeric sugars. In this study, we used physiologically immature corn silage (CS and matured whole corn plants (WCP as feedstocks to produce ethanol using ammonia fiber expansion (AFEX pretreatment followed by enzymatic hydrolysis (at low enzyme loadings and cofermentation (for both glucose and xylose using a cellulase-amylase-based cocktail and a recombinant Saccharomyces cerevisiae 424A (LNH-ST strain, respectively. The effect on hydrolysis yields of AFEX pretreatment conditions and a starch/cellulose-degrading enzyme addition sequence for both substrates was also studied. Results AFEX-pretreated starch-rich substrates (for example, corn grain, soluble starch had a 1.5-3-fold higher enzymatic hydrolysis yield compared with the untreated substrates. Sequential addition of cellulases after hydrolysis of starch within WCP resulted in 15-20% higher hydrolysis yield compared with simultaneous addition of hydrolytic enzymes. AFEX-pretreated CS gave 70% glucan conversion after 72 h of hydrolysis for 6% glucan loading (at 8 mg total enzyme loading per gram glucan. Microbial inoculation of CS before ensilation yielded a 10-15% lower glucose hydrolysis yield for the pretreated substrate, due to loss in starch content. Ethanol fermentation of AFEX-treated (at 6% w/w glucan loading CS hydrolyzate (resulting

Enzymatic digestibility and ethanol fermentability of AFEX-treated starch-rich lignocellulosics such as corn silage and whole corn plant

Science.gov (United States)

2010-01-01

Background Corn grain is an important renewable source for bioethanol production in the USA. Corn ethanol is currently produced by steam liquefaction of starch-rich grains followed by enzymatic saccharification and fermentation. Corn stover (the non-grain parts of the plant) is a potential feedstock to produce cellulosic ethanol in second-generation biorefineries. At present, corn grain is harvested by removing the grain from the living plant while leaving the stover behind on the field. Alternatively, whole corn plants can be harvested to cohydrolyze both starch and cellulose after a suitable thermochemical pretreatment to produce fermentable monomeric sugars. In this study, we used physiologically immature corn silage (CS) and matured whole corn plants (WCP) as feedstocks to produce ethanol using ammonia fiber expansion (AFEX) pretreatment followed by enzymatic hydrolysis (at low enzyme loadings) and cofermentation (for both glucose and xylose) using a cellulase-amylase-based cocktail and a recombinant Saccharomyces cerevisiae 424A (LNH-ST) strain, respectively. The effect on hydrolysis yields of AFEX pretreatment conditions and a starch/cellulose-degrading enzyme addition sequence for both substrates was also studied. Results AFEX-pretreated starch-rich substrates (for example, corn grain, soluble starch) had a 1.5-3-fold higher enzymatic hydrolysis yield compared with the untreated substrates. Sequential addition of cellulases after hydrolysis of starch within WCP resulted in 15-20% higher hydrolysis yield compared with simultaneous addition of hydrolytic enzymes. AFEX-pretreated CS gave 70% glucan conversion after 72 h of hydrolysis for 6% glucan loading (at 8 mg total enzyme loading per gram glucan). Microbial inoculation of CS before ensilation yielded a 10-15% lower glucose hydrolysis yield for the pretreated substrate, due to loss in starch content. Ethanol fermentation of AFEX-treated (at 6% w/w glucan loading) CS hydrolyzate (resulting in 28 g/L ethanol

Volatility spillovers in China’s crude oil, corn and fuel ethanol markets

International Nuclear Information System (INIS)

Haixia, Wu; Shiping, Li

2013-01-01

Price volatility spillovers among China’s crude oil, corn and fuel ethanol markets are analyzed based on weekly price data from September 5, 2003 to August 31, 2012, employing the univariate EGARCH model and the BEKK-MVGARCH model, respectively. The empirical results indicate a higher interaction among crude oil, corn and fuel ethanol markets after September, 2008. In the overall sample period, the results simultaneously provide strong evidence that there exist unidirectional spillover effects from the crude oil market to the corn and fuel ethanol markets, and double-directional spillovers between the corn market and the fuel ethanol market. However, the spillover effects from the corn and fuel ethanol markets to the crude oil market are not significant. -- Highlights: •Employing univariate EGARCH model and BEKK-MVGARCH model, respectively. Unidirectional spillover effects from crude oil market to corn and fuel ethanol markets. •Double-directional spillovers between corn market and fuel ethanol market. •The spillover effects from corn and fuel ethanol markets to crude oil market are not significant. •The empirical results indicate a higher interaction among crude oil, corn and fuel ethanol markets after September, 2008

An energy analysis of ethanol from cellulosic feedstock. Corn stover

Energy Technology Data Exchange (ETDEWEB)

Luo, Lin; Van der Voet, Ester; Huppes, Gjalt [Institute of Environmental Sciences (CML), Leiden University, P.O. Box 9518, 2300 RA, Leiden (Netherlands)

2009-10-15

The shift from fossil resources to renewables for energy and materials production has been the driving force for research on energy analysis and environmental impact assessment of bio-based production. This study presents a detailed energy analysis of corn stover based ethanol production using advanced cellulosic technologies. The method used differs from that in LCA and from major studies on the subject as published in Science in two respects. First, it accounts for all the co-products together and so mainly avoids the allocation problems which plague all LCA studies explicitly and other studies implicitly. Second, the system boundaries only involve the content of the energy products used in the system but not the production processes of these energy products, like refining and electricity production. We normalized the six Science studies to this unified method. The resulting values of the total energy product use in both agricultural production and biomass conversion to ethanol are lower than these literature values. LCA-type of values including energy conversion would systematically be higher, in our case study around 45%. The net energy value of cellulosic ethanol production is substantially higher than the ones of the corn-based technologies, and it is similar to incineration and gasification for electricity production. The detailed analysis of energy inputs indicates opportunities to optimize the system. This form of energy analysis helps establishing models for the analysis of more complex systems such as biorefineries. (author)

High temperature dilute phosphoric acid pretreatment of corn stover for furfural and ethanol production

Science.gov (United States)

Furfural was produced from corn stover by one stage pretreatment process using dilute H3PO4 and solid residues following furfural production were used for ethanol production by Saccharomyces cerevisiae NRRL- Y2034. A series of experiments were conducted at varied temperatures (140-200 oC) and acid ...

Fate of Fumonisin B1 in Naturally Contaminated Corn during Ethanol Fermentation

Science.gov (United States)

Bothast, R. J.; Bennett, G. A.; Vancauwenberge, J. E.; Richard, J. L.

1992-01-01

Two lots of corn naturally contaminated with fumonisin B1 (15 and 36 ppm) and a control lot (no fumonisin B1 detected) were used as substrates for ethanol production in replicate 8.5-liter yeast fermentations. Ethanol yields were 8.8% for both the control and low-fumonisin corn, while the high-fumonisin corn contained less starch and produced 7.2% ethanol. Little degradation of fumonisin occurred during fermentation, and most was recovered in the distillers' grains, thin stillage, and distillers' solubles fractions. No toxin was detected in the distilled alcohol or centrifuge solids. Ethanol fermentation of fumonisin-contaminated corn coupled with effective detoxification of distillers' grains and aqueous stillage is suggested as a practical process strategy for salvaging contaminated corn. PMID:16348623

Environmental aspects of ethanol derived from no-tilled corn grain: nonrenewable energy consumption and greenhouse gas emissions

International Nuclear Information System (INIS)

Kim, Seungdo; Dale, Bruce E.

2005-01-01

Nonrenewable energy consumption and greenhouse gas (GHG) emissions associated with ethanol (a liquid fuel) derived from corn grain produced in selected counties in Illinois, Indiana, Iowa, Michigan, Minnesota, Ohio, and Wisconsin are presented. Corn is cultivated under no-tillage practice (without plowing). The system boundaries include corn production, ethanol production, and the end use of ethanol as a fuel in a midsize passenger car. The environmental burdens in multi-output biorefinery processes (e.g., corn dry milling and wet milling) are allocated to the ethanol product and its various coproducts by the system expansion allocation approach. The nonrenewable energy requirement for producing 1 kg of ethanol is approximately 13.4-21.5 MJ (based on lower heating value), depending on corn milling technologies employed. Thus, the net energy value of ethanol is positive; the energy consumed in ethanol production is less than the energy content of the ethanol (26.8 MJ kg -1 ). In the GHG emissions analysis, nitrous oxide (N 2 O) emissions from soil and soil organic carbon levels under corn cultivation in each county are estimated by the DAYCENT model. Carbon sequestration rates range from 377 to 681 kg C ha -1 year -1 and N 2 O emissions from soil are 0.5-2.8 kg N ha -1 year -1 under no-till conditions. The GHG emissions assigned to 1 kg of ethanol are 260-922 g CO 2 eq. under no-tillage. Using ethanol (E85) fuel in a midsize passenger vehicle can reduce GHG emissions by 41-61% km -1 driven, compared to gasoline-fueled vehicles. Using ethanol as a vehicle fuel, therefore, has the potential to reduce nonrenewable energy consumption and GHG emissions

The causes and unintended consequences of a paradigm shift in corn production practices

International Nuclear Information System (INIS)

Fausti, Scott W.

2015-01-01

Highlights: • Biotechnology adoption and the U.S. corn production system are causally linked. • U.S. agriculture and energy policy choices merged to incentivize U.S. corn production. • U.S. biofuel energy policy contributed to the adoption of Bt corn seed technology. • Policy alternatives to modify the corn-based ethanol production system are provided. - Abstract: Independent but simultaneously occurring changes in U.S. agricultural and energy policies in conjunction with advances in biotechnology converged to create an economic and regulatory environment that incentivized corn acreage expansion. Advancements in Bt seed and ethanol production technologies contributed to scale efficiency gains in corn and biofuel production. These advancements were accompanied by changes in market forces that altered the balance between corn and other agricultural crop production. The causal linkages among Bt adoption, ethanol production, and corn production are explored along with a discussion of how this shift toward corn production generated unexpected economic and environmental consequences. Alternative policy solutions to mitigate the negative consequences and enhance the resiliency of U.S. agriculture are discussed

Development of corn silk as a biocarrier for Zymomonas mobilis biofilms in ethanol production from rice straw.

Science.gov (United States)

Todhanakasem, Tatsaporn; Tiwari, Rashmi; Thanonkeo, Pornthap

2016-01-01

Z. mobilis cell immobilization has been proposed as an effective means of improving ethanol production. In this work, polystyrene and corn silk were used as biofilm developmental matrices for Z. mobilis ethanol production with rice straw hydrolysate as a substrate. Rice straw was hydrolyzed by dilute sulfuric acid (H2SO4) and enzymatic hydrolysis. The final hydrolysate contained furfural (271.95 ± 76.30 ppm), 5-hydroxymethyl furfural (0.07 ± 0.00 ppm), vanillin (1.81 ± 0.00 ppm), syringaldehyde (5.07 ± 0.83 ppm), 4-hydroxybenzaldehyde (4-HB) (2.39 ± 1.20 ppm) and acetic acid (0.26 ± 0.08%). Bacterial attachment or biofilm formation of Z. mobilis strain TISTR 551 on polystyrene and delignified corn silk carrier provided significant ethanol yields. Results showed up to 0.40 ± 0.15 g ethanol produced/g glucose consumed when Z. mobilis was immobilized on a polystyrene carrier and 0.51 ± 0.13 g ethanol produced/g glucose consumed when immobilized on delignified corn silk carrier under batch fermentation by Z. mobilis TISTR 551 biofilm. The higher ethanol yield from immobilized, rather than free living, Z. mobilis could possibly be explained by a higher cell density, better control of anaerobic conditions and higher toxic tolerance of Z. mobilis biofilms over free cells.

Update of distillers grains displacement ratios for corn ethanol life-cycle analysis.

Energy Technology Data Exchange (ETDEWEB)

Arora, S.; Wu, M.; Wang, M.; Energy Systems

2011-02-01

Production of corn-based ethanol (either by wet milling or by dry milling) yields the following coproducts: distillers grains with solubles (DGS), corn gluten meal (CGM), corn gluten feed (CGF), and corn oil. Of these coproducts, all except corn oil can replace conventional animal feeds, such as corn, soybean meal, and urea. Displacement ratios of corn-ethanol coproducts including DGS, CGM, and CGF were last updated in 1998 at a workshop at Argonne National Laboratory on the basis of input from a group of experts on animal feeds, including Prof. Klopfenstein (University of Nebraska, Lincoln), Prof. Berger (University of Illinois, Urbana-Champaign), Mr. Madson (Rapheal Katzen International Associates, Inc.), and Prof. Trenkle (Iowa State University) (Wang 1999). Table 1 presents current dry milling coproduct displacement ratios being used in the GREET model. The current effort focuses on updating displacement ratios of dry milling corn-ethanol coproducts used in the animal feed industry. Because of the increased availability and use of these coproducts as animal feeds, more information is available on how these coproducts replace conventional animal feeds. To glean this information, it is also important to understand how industry selects feed. Because of the wide variety of available feeds, animal nutritionists use commercial software (such as Brill Formulation{trademark}) for feed formulation. The software recommends feed for the animal on the basis of the nutritional characteristics, availability, and price of various animal feeds, as well as on the nutritional requirements of the animal (Corn Refiners Association 2006). Therefore, feed formulation considers both the economic and the nutritional characteristics of feed products.

Fate of Fumonisin B1 in Naturally Contaminated Corn during Ethanol Fermentation

OpenAIRE

Bothast, R. J.; Bennett, G. A.; Vancauwenberge, J. E.; Richard, J. L.

1992-01-01

Two lots of corn naturally contaminated with fumonisin B1 (15 and 36 ppm) and a control lot (no fumonisin B1 detected) were used as substrates for ethanol production in replicate 8.5-liter yeast fermentations. Ethanol yields were 8.8% for both the control and low-fumonisin corn, while the high-fumonisin corn contained less starch and produced 7.2% ethanol. Little degradation of fumonisin occurred during fermentation, and most was recovered in the distillers' grains, thin stillage, and distill...

Life-cycle energy and greenhouse gas emission impacts of different corn ethanol plant types

International Nuclear Information System (INIS)

Wang, Michael; Wu, May; Hong Huo

2007-01-01

Since the United States began a programme to develop ethanol as a transportation fuel, its use has increased from 175 million gallons in 1980 to 4.9 billion gallons in 2006. Virtually all of the ethanol used for transportation has been produced from corn. During the period of fuel ethanol growth, corn farming productivity has increased dramatically, and energy use in ethanol plants has been reduced by almost by half. The majority of corn ethanol plants are powered by natural gas. However, as natural gas prices have skyrocketed over the last several years, efforts have been made to further reduce the energy used in ethanol plants or to switch from natural gas to other fuels, such as coal and wood chips. In this paper, we examine nine corn ethanol plant types-categorized according to the type of process fuels employed, use of combined heat and power, and production of wet distiller grains and solubles. We found that these ethanol plant types can have distinctly different energy and greenhouse gas emission effects on a full fuel-cycle basis. In particular, greenhouse gas emission impacts can vary significantly-from a 3% increase if coal is the process fuel to a 52% reduction if wood chips are used. Our results show that, in order to achieve energy and greenhouse gas emission benefits, researchers need to closely examine and differentiate among the types of plants used to produce corn ethanol so that corn ethanol production would move towards a more sustainable path

Effect of the corn breaking method on oil distribution between stillage phases of dry-grind corn ethanol production.

Science.gov (United States)

Wang, H; Wang, T; Johnson, L A; Pometto, A L

2008-11-12

The majority of fuel ethanol in the United States is produced by using the dry-grind corn ethanol process. The corn oil that is contained in the coproduct, distillers' dried grains with solubles (DDGS), can be recovered for use as a biodiesel feedstock. Oil removal will also improve the feed quality of DDGS. The most economical way to remove oil is considered to be at the centrifugation step for separating thin stillage (liquid) from coarse solids after distilling the ethanol. The more oil there is in the liquid, the more it can be recovered by centrifugation. Therefore, we studied the effects of corn preparation and grinding methods on oil distribution between liquid and solid phases. Grinding the corn to three different particle sizes, flaking, flaking and grinding, and flaking and extruding were used to break up the corn kernel before fermentation, and their effects on oil distribution between the liquid and solid phases were examined by simulating an industrial decanter centrifuge. Total oil contents were measured in the liquid and solids after centrifugation. Dry matter yield and oil partitioning in the thin stillage were highly positively correlated. Flaking slightly reduced bound fat. The flaked and then extruded corn meal released the highest amount of free oil, about 25% compared to 7% for the average of the other treatments. The freed oil from flaking, however, became nonextractable after the flaked corn was ground. Fine grinding alone had little effect on oil partitioning.

Reducing life cycle greenhouse gas emissions of corn ethanol by integrating biomass to produce heat and power at ethanol plants

International Nuclear Information System (INIS)

Kaliyan, Nalladurai; Morey, R. Vance; Tiffany, Douglas G.

2011-01-01

A life-cycle assessment (LCA) of corn ethanol was conducted to determine the reduction in the life-cycle greenhouse gas (GHG) emissions for corn ethanol compared to gasoline by integrating biomass fuels to replace fossil fuels (natural gas and grid electricity) in a U.S. Midwest dry-grind corn ethanol plant producing 0.19 hm 3 y -1 of denatured ethanol. The biomass fuels studied are corn stover and ethanol co-products [dried distillers grains with solubles (DDGS), and syrup (solubles portion of DDGS)]. The biomass conversion technologies/systems considered are process heat (PH) only systems, combined heat and power (CHP) systems, and biomass integrated gasification combined cycle (BIGCC) systems. The life-cycle GHG emission reduction for corn ethanol compared to gasoline is 38.9% for PH with natural gas, 57.7% for PH with corn stover, 79.1% for CHP with corn stover, 78.2% for IGCC with natural gas, 119.0% for BIGCC with corn stover, and 111.4% for BIGCC with syrup and stover. These GHG emission estimates do not include indirect land use change effects. GHG emission reductions for CHP, IGCC, and BIGCC include power sent to the grid which replaces electricity from coal. BIGCC results in greater reductions in GHG emissions than IGCC with natural gas because biomass is substituted for fossil fuels. In addition, underground sequestration of CO 2 gas from the ethanol plant's fermentation tank could further reduce the life-cycle GHG emission for corn ethanol by 32% compared to gasoline.

Optimization of a corn steep medium for production of ethanol from synthesis gas fermentation by Clostridium ragsdalei.

Science.gov (United States)

Saxena, Jyotisna; Tanner, Ralph S

2012-04-01

Fermentation of biomass derived synthesis gas to ethanol is a sustainable approach that can provide more usable energy and environmental benefits than food-based biofuels. The effects of various medium components on ethanol production by Clostridium ragsdalei utilizing syngas components (CO:CO(2)) were investigated, and corn steep liquor (CSL) was used as an inexpensive nutrient source for ethanol production by C. ragsdalei. Elimination of Mg(2+), NH(4) (+) and PO(4) (3-) decreased ethanol production from 38 to 3.7, 23 and 5.93 mM, respectively. Eliminating Na(+), Ca(2+), and K(+) or increasing Ca(2+), Mg(2+), K(+), NH(4) (+) and PO(4) (3-) concentrations had no effect on ethanol production. However, increased Na(+) concentration (171 mM) inhibited growth and ethanol production. Yeast extract (0.5 g l(-1)) and trace metals were necessary for growth of C. ragsdalei. CSL alone did not support growth and ethanol production. Nutrients limiting in CSL were trace metals, NH(4) (+) and reducing agent (Cys: cysteine sulfide). Supplementation of trace metals, NH(4) (+) and CyS to CSL (20 g l(-1), wet weight basis) yielded better growth and similar ethanol production as compared to control medium. Using 10 g l(-1), the nutritional limitation led to reduced ethanol production. Higher concentrations of CSL (50 and 100 g l(-1)) were inhibitory for cell growth and ethanol production. The CSL could replace yeast extract, vitamins and minerals (excluding NH(4) (+)). The optimized CSL medium produced 120 and 50 mM of ethanol and acetate, respectively. The CSL could provide as an inexpensive source of most of the nutrients required for the syngas fermentation, and thus could improve the economics of ethanol production from biomass derived synthesis gas by C. ragsdalei.

Ethanol extraction of phytosterols from corn fiber

Science.gov (United States)

Abbas, Charles; Beery, Kyle E.; Binder, Thomas P.; Rammelsberg, Anne M.

2010-11-16

The present invention provides a process for extracting sterols from a high solids, thermochemically hydrolyzed corn fiber using ethanol as the extractant. The process includes obtaining a corn fiber slurry having a moisture content from about 20 weight percent to about 50 weight percent solids (high solids content), thermochemically processing the corn fiber slurry having high solids content of 20 to 50% to produce a hydrolyzed corn fiber slurry, dewatering the hydrolyzed corn fiber slurry to achieve a residual corn fiber having a moisture content from about 30 to 80 weight percent solids, washing the residual corn fiber, dewatering the washed, hydrolyzed corn fiber slurry to achieve a residual corn fiber having a moisture content from about 30 to 80 weight percent solids, and extracting the residual corn fiber with ethanol and separating at least one sterol.

Water and Land Use Efficiency in Current and Potential Future US Corn and Brazilian Sugarcane Ethanol Systems

Science.gov (United States)

Warner, E. S.; Zhang, Y.; Newmark, R. L.

2012-12-01

Biofuels represent an opportunity for domestic fuel production from renewable energy sources with potential environmental and social benefits such as reducing greenhouse gas (GHG) and promoting rural development. However, as demand for biofuel continues to increase worldwide, concerns about land competition between food and fuel, excessive water usage and other unintended environmental consequences have grown. Through a comparative study between US corn ethanol and Brazilian sugarcane ethanol, we examine the energy, land, water and GHG performance of the two largest industrial fuel ethanol production systems in the world. Our comparisons include current and potential future systems with improved agronomic practices, crop yields, ethanol conversion processes, and utilization of agricultural residues. Our results suggest that the average water footprints of US corn ethanol and Brazilian sugarcane ethanol are fairly close (108 and 110 m3/GJ of ethanol, respectively) while the variations can range from 50 to 250 m3/GJ for sugarcane ethanol and 50 to380 m3/GJ for corn ethanol. Results emphasize the need to examine the water footprint within the context of local and regional climatic variability, water availability, competing uses (e.g. agricultural, industrial, and municipal water needs) and other ecosystem constraints. Research is under way (at the National Renewable Energy Laboratory and other institutions) to develop models to analyze water supply and demand at the watershed-scale for current and future biomass production, and to understand the tradeoffs among water supply, demand and quality due to more intensive agricultural practices and expansion of biofuels. Land use efficiency metrics, with regards to life cycle GHG emissions (without land use change) savings through gasoline displacement with ethanol, illustrate the progression of the biofuel industry and the importance of maximizing bioenergy production by utilizing both the crops and the residues. A recent

Bioconversion of corn stover hydrolysate to ethanol by a recombinant yeast strain

Energy Technology Data Exchange (ETDEWEB)

Zhao, Jing; Xia, Liming

2010-12-15

Three corn stover hydrolysates, enzymatic hydrolysates prepared from acid and alkaline pretreatments separately and hemicellulosic hydrolysate prepared from acid pretreatment, were evaluated in composition and fermentability. For enzymatic hydrolysate from alkaline pretreatment, ethanol yield on fermentable sugars and fermentation efficiency reached highest among the three hydrolysates; meanwhile, ethanol yield on dry corn stover reached 0.175 g/g, higher than the sum of those of two hydrolysates from acid pretreatment. Fermentation process of the enzymatic hydrolysate from alkaline pretreatment was further investigated using free and immobilized cells of recombinant Saccharomyces cerevisiae ZU-10. Concentrated hydrolysate containing 66.9 g/L glucose and 32.1 g/L xylose was utilized. In the fermentation with free cells, 41.2 g/L ethanol was obtained within 72 h with an ethanol yield on fermentable sugars of 0.416 g/g. Immobilized cells greatly enhanced the ethanol productivity, while the ethanol yield on fermentable sugars of 0.411 g/g could still be reached. Repeated batch fermentation with immobilized cells was further attempted up to six batches. The ethanol yield on fermentable sugars maintained above 0.403 g/g with all glucose and more than 92.83% xylose utilized in each batch. These results demonstrate the feasibility and efficiency of ethanol production from corn stover hydrolysates. (author)

Using a spark-spread valuation to investigate the impact of corn-gasoline correlation on ethanol plant valuation

International Nuclear Information System (INIS)

Kirby, Natasha; Davison, Matt

2010-01-01

Corn ethanol plants have been criticized for a number of reasons in recent years. This paper provides another ground for criticizing these plants. Historical corn and gasoline prices are uncorrelated, but widespread adoption of corn ethanol production might reasonably lead to future correlation between these prices. We present a real options - like valuation of an ethanol plant as a spark spread between the corn price and the gasoline price. This analysis shows that the value of an ethanol plant monotonically decreases with increasing correlation and the optimal production schedule greatly depends on the correlation. Even relatively small new correlations can result in a significant proportional value decrease; a 50% correlation between corn and gasoline causes ethanol plants to lose 10% of their value. The limiting case of full correlation would lead to a 30% value loss. (author)

A new magnesium bisulfite pretreatment (MBSP) development for bio-ethanol production from corn stover.

Science.gov (United States)

Yu, Heng; Ren, Jiwei; Liu, Lei; Zheng, Zhaojuan; Zhu, Junjun; Yong, Qiang; Ouyang, Jia

2016-01-01

This study established a new more neutral magnesium bisulfate pretreatment (MBSP) using magnesium bisulfate as sulfonating agent for improving the enzymatic hydrolysis efficiency of corn stover. Using the MBSP with 5.21% magnesium bisulfate, 170°C and pH 5.2 for 60 min, about 90% of lignin and 80% of hemicellulose were removed from biomass and more than 90% cellulose conversion of substrate was achieved after 48 h hydrolysis. About 6.19 kg raw corn stover could produce 1 kg ethanol by Saccharomyces cerevisiae. Meanwhile, MBSP also could protect sugars from excessive degradation, prevent fermentation inhibition formation and directly convert the hemicelluloses into xylooligosaccharides as higher-value products. These results suggested that the MBSP method offers an alternative approach to the efficient conversion of nonwoody lignocellulosic biomass to ethanol and had broad space for development. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of potassium sorbate and Lactobacillus plantarum MTD1 on production of ethanol and other volatile organic compounds in corn silage

DEFF Research Database (Denmark)

Hafner, Sasha D.; Windle, Michelle; Merrill, Caitlyn

2015-01-01

was to evaluate the effect of additives on production of nine silage VOC in corn silage, including compounds thought to contribute to poor air quality or affect feed intake (alcohols: methanol, ethanol, 1-propanol; esters: methyl acetate, ethyl acetate, ethyl lactate; and aldehydes: acetaldehyde, valeraldehyde....... These results provide additional evidence that potassium sorbate is an effective additive for reducing production of ethanol and ethyl esters in corn silage. Combining potassium sorbate with L. plantarum may provide additional benefits, although the persistence of this effect for silages with higher VOC...

The effect of ethanol listing on corn prices: Evidence from spot and futures markets

International Nuclear Information System (INIS)

Demirer, Rıza; Kutan, Ali M.; Shen, Fanglin

2012-01-01

The use of corn for ethanol has been the topic of heated discussions in the media and among policy makers. As part of this debate, some observers have argued that the use of corn in the production of ethanol has had adverse effects on corn prices. This paper contributes to this reviving debate by examining the impact of the listing of ethanol futures in the Chicago Board of Trade on the spot and futures prices for corn. We find a significant listing effect, indicating that the listing of ethanol has had a positive contribution to both price and volatility in the corn market, especially in the spot and the shorter maturity futures contracts, and mostly through its interaction with trading volume in the corn market. We discuss the policy implications of the findings for investors and its relevance for the ongoing debate on US energy policy. We conclude with some suggestions for future research.

Continuous high-solids corn liquefaction and fermentation with stripping of ethanol.

Science.gov (United States)

Taylor, Frank; Marquez, Marco A; Johnston, David B; Goldberg, Neil M; Hicks, Kevin B

2010-06-01

Removal of ethanol from the fermentor during fermentation can increase productivity and reduce the costs for dewatering the product and coproduct. One approach is to recycle the fermentor contents through a stripping column, where a non-condensable gas removes ethanol to a condenser. Previous research showed that this approach is feasible. Savings of $0.03 per gallon were predicted at 34% corn dry solids. Greater savings were predicted at higher concentration. Now the feasibility has been demonstrated at over 40% corn dry solids, using a continuous corn liquefaction system. A pilot plant, that continuously fed corn meal at more than one bushel (25 kg) per day, was operated for 60 consecutive days, continuously converting 95% of starch and producing 88% of the maximum theoretical yield of ethanol. A computer simulation was used to analyze the results. The fermentation and stripping systems were not significantly affected when the CO(2) stripping gas was partially replaced by nitrogen or air, potentially lowering costs associated with the gas recycle loop. It was concluded that previous estimates of potential cost savings are still valid. (c) 2010. Published by Elsevier Ltd. All rights reserved.

A whole cell biocatalyst for cellulosic ethanol production from dilute acid-pretreated corn stover hydrolyzates

Energy Technology Data Exchange (ETDEWEB)

Ryu, Seunghyun; Karim, Muhammad Nazmul [Texas Tech Univ., Lubbock, TX (United States). Dept. of Chemical Engineering

2011-08-15

In this research, a recombinant whole cell biocatalyst was developed by expressing three cellulases from Clostridium cellulolyticum - endoglucanase (Cel5A), exoglucanase (Cel9E), and {beta}-glucosidase - on the surface of the Escherichia coli LY01. The modified strain is identified as LY01/pRE1H-AEB. The cellulases were displayed on the surface of the cell by fusing with an anchor protein, PgsA. The developed whole cell biocatalyst was used for single-step ethanol fermentation using the phosphoric acid-swollen cellulose (PASC) and the dilute acid-pretreated corn stover. Ethanol production was 3.59 {+-} 0.15 g/L using 10 g/L of PASC, which corresponds to a theoretical yield of 95.4 {+-} 0.15%. Ethanol production was 0.30 {+-} 0.02 g/L when 1 g/L equivalent of glucose in the cellulosic fraction of the dilute sulfuric acid-pretreated corn stover (PCS) was fermented for 84 h. A total of 0.71 {+-} 0.12 g/L ethanol was produced in 48 h when the PCS was fermented in the simultaneous saccharification and co-fermentation mode using the hemicellulosic (1 g/L of total soluble sugar) and as well as the cellulosic (1 g/L of glucose equivalent) parts of PCS. In a control experiment, 0.48 g/L ethanol was obtained from 1 g/L of hemicellulosic PCS. It was concluded that the whole cell biocatalyst could convert both cellulosic and hemicellulosic substrates into ethanol in a single reactor. The developed C. cellulolyticum-E. coli whole cell biocatalyst also overcame the incompatible temperature problem of the frequently reported fungal-yeast systems. (orig.)

Development of rapid bioconversion with integrated recycle technology for ethanol production from extractive ammonia pretreated corn stover.

Science.gov (United States)

Jin, Mingjie; Liu, Yanping; da Costa Sousa, Leonardo; Dale, Bruce E; Balan, Venkatesh

2017-08-01

High enzyme loading and low productivity are two major issues impeding low cost ethanol production from lignocellulosic biomass. This work applied rapid bioconversion with integrated recycle technology (RaBIT) and extractive ammonia (EA) pretreatment for conversion of corn stover (CS) to ethanol at high solids loading. Enzymes were recycled via recycling unhydrolyzed solids. Enzymatic hydrolysis with recycled enzymes and fermentation with recycled yeast cells were studied. Both enzymatic hydrolysis time and fermentation time were shortened to 24 h. Ethanol productivity was enhanced by two times and enzyme loading was reduced by 30%. Glucan and xylan conversions reached as high as 98% with an enzyme loading of as low as 8.4 mg protein per g glucan. The overall ethanol yield was 227 g ethanol/kg EA-CS (191 g ethanol/kg untreated CS). Biotechnol. Bioeng. 2017;114: 1713-1720. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Ethanol production from hydrothermal pretreated corn stover with a loop reactor

Energy Technology Data Exchange (ETDEWEB)

Xu, Jian; Thomsen, Mette Hedegaard; Thomsen, Anne Belinda [National Lab for Sustainable Energy, Biosystems Department, Risoe-DTU, P.O. Box 49, DK-4000 Roskilde (Denmark)

2010-03-15

Hydrothermal pretreatment on raw corn stover (RCS) with a loop reactor was investigated at 195 C for different times varying between 10 min and 30 min. After pretreatment, the slurry was separated into water-insoluble solid (WIS) and liquid phase. Glucan and xylan were found in the both phases. The pretreatment condition showed a significant impact on xylan recovery. As the pretreatment time prolonged from 10 min to 30 min, the xylan recovery from liquid phase changed between 39.5% and 45.6% and the total xylan recoveries decreased from 84.7% to 61.6%. While the glucan recovery seemed not sensitive to the different pretreatment times. The glucan recovered from liquid was from 4.9% to 5.6% and the total glucan recoveries from all the pretreatments were higher than 98%. Besides HMF and furfural, acetic, lactic, formic and glycolic acids were also found in the liquid phase. All the concentrations of these potential inhibitors were lower enough not to affect the activity of the Saccharomyces cerevisiae (S. cerevisiae). Compared with the ethanol production of 32.4% from the RCS with S. cerevisiae, all the WISs gave higher ethanol productions ranging between 61.2% and 71.2%. When the xylan was taken into consideration, the best pretreatment condition would be 195 C, 15 min and the estimated total ethanol production was 201 g kg{sup -1} RCS by assuming the fermentation of both C-6 and C-5 with the ethanol yield of 0.51 g g{sup -1} and 0.47 g g{sup -1}, respectively. (author)

Ethanol production from hydrothermal pretreated corn stover with a loop reactor

International Nuclear Information System (INIS)

Xu, Jian; Thomsen, Mette Hedegaard; Thomsen, Anne Belinda

2010-01-01

Hydrothermal pretreatment on raw corn stover (RCS) with a loop reactor was investigated at 195 o C for different times varying between 10 min and 30 min. After pretreatment, the slurry was separated into water-insoluble solid (WIS) and liquid phase. Glucan and xylan were found in the both phases. The pretreatment condition showed a significant impact on xylan recovery. As the pretreatment time prolonged from 10 min to 30 min, the xylan recovery from liquid phase changed between 39.5% and 45.6% and the total xylan recoveries decreased from 84.7% to 61.6%. While the glucan recovery seemed not sensitive to the different pretreatment times. The glucan recovered from liquid was from 4.9% to 5.6% and the total glucan recoveries from all the pretreatments were higher than 98%. Besides HMF and furfural, acetic, lactic, formic and glycolic acids were also found in the liquid phase. All the concentrations of these potential inhibitors were lower enough not to affect the activity of the Saccharomyces cerevisiae (S. cerevisiae). Compared with the ethanol production of 32.4% from the RCS with S. cerevisiae, all the WISs gave higher ethanol productions ranging between 61.2% and 71.2%. When the xylan was taken into consideration, the best pretreatment condition would be 195 o C, 15 min and the estimated total ethanol production was 201 g kg -1 RCS by assuming the fermentation of both C-6 and C-5 with the ethanol yield of 0.51 g g -1 and 0.47 g g -1 , respectively.

Heat recovery investigation from dryer–thermal oxidizer system in corn-ethanol plants

International Nuclear Information System (INIS)

Olszewski, Pawel

2015-01-01

In recent years, annual corn ethanol production in the U.S. has exceeded 13,298,000,000 gallons. However, net energy balance for this sector became a subject of controversy in many discussions. The aim of the presented research is an investigation of thermal improvement opportunities in a corn ethanol plant. For this purpose, a complex mathematical model was developed for a dryer–thermal oxidizer system. Three variants were subjected thermodynamic analyses: one state of the art system and two proposed system modifications. The properties of humid gas, a mixture of combustion products and moisture evaporated from distiller's grain, were updated based on the steam properties according to the formulation proposed by the International Association for the Properties of Water and Steam. All calculations were performed by uniquely-developed C++ code. The results indicate major potential for improvement in the following areas: (i) water recovery from humid gas; (ii) heat recovery from moisture condensation – max. 44% of total primary energy usage (TPEU); and (iii) fuel savings by reduction of humid gas flow through a thermal oxidizer – max. 1.4% of TPEU. Also the presented analysis can be a starting point for further modifications in real corn ethanol manufacturing applications, leading towards pilot system implementation. - Highlights: • Mathematical model for dryer–oxidizer system in a corn ethanol plant was proposed. • Three configurations were discussed: with intercooler, regenerator, and recuperator. • Recovery rate of water condensed at various conditions and locations was quantified. • Heat recovery possibilities at various temperatures and locations have been assessed. • Energy savings in thermal oxidizer due to preliminary condensation were calculated

Energy and greenhouse gas emission effects of corn and cellulosic ethanol with technology improvements and land use changes

International Nuclear Information System (INIS)

Wang, Michael Q.; Han, Jeongwoo; Haq, Zia; Tyner, Wallace E.; Wu, May; Elgowainy, Amgad

2011-01-01

Use of ethanol as a transportation fuel in the United States has grown from 76 dam 3 in 1980 to over 40.1 hm 3 in 2009 - and virtually all of it has been produced from corn. It has been debated whether using corn ethanol results in any energy and greenhouse gas benefits. This issue has been especially critical in the past several years, when indirect effects, such as indirect land use changes, associated with U.S. corn ethanol production are considered in evaluation. In the past three years, modeling of direct and indirect land use changes related to the production of corn ethanol has advanced significantly. Meanwhile, technology improvements in key stages of the ethanol life cycle (such as corn farming and ethanol production) have been made. With updated simulation results of direct and indirect land use changes and observed technology improvements in the past several years, we conducted a life-cycle analysis of ethanol and show that at present and in the near future, using corn ethanol reduces greenhouse gas emission by more than 20%, relative to those of petroleum gasoline. On the other hand, second-generation ethanol could achieve much higher reductions in greenhouse gas emissions. In a broader sense, sound evaluation of U.S. biofuel policies should account for both unanticipated consequences and technology potentials. We maintain that the usefulness of such evaluations is to provide insight into how to prevent unanticipated consequences and how to promote efficient technologies with policy intervention.

Evaluating fuel ethanol feedstocks from energy policy perspectives: A comparative energy assessment of corn and corn stover

International Nuclear Information System (INIS)

Lavigne, Amanda; Powers, Susan E.

2007-01-01

Concerns surrounding the continued, un-checked use of petroleum-based fuels in the transportation sector, the search for more sustainable, renewable alternatives, and the constraints of the existing supply infrastructure in the United States have placed a spotlight on biomass-derived fuels. The central question of the ethanol debate has changed from 'Should we make ethanol?' to 'From what should we make ethanol?' emphasizing the importance of understanding the differences between specific biomass supply systems for fuel ethanol. When presented with numerous options, the priorities of an individual decision maker will define which feedstock alternative is the most appropriate choice for development from their perspective. This paper demonstrates how energy data can be successfully used to quantify assessment metrics beyond a standard net energy value calculation, thus quantifying the relative 'value' of ethanol supply systems. This value is defined based on decision-maker priorities that were adopted from national energy policy priorities: increased national energy security and increased conservation of energy resources. Nine energy assessment metrics that quantify detailed system energy data are calculated and a straightforward comparative assessment is performed between corn and corn stover feedstocks produced under the same farm scenario. Corn stover is shown to be more compatible with the national energy policy priorities and it is recommended that additional research be performed on utilizing this feedstock from the corn farm

Simultaneous saccharification and cofermentation of lignocellulosic residues from commercial furfural production and corn kernels using different nutrient media

Directory of Open Access Journals (Sweden)

Cristhian Carrasco

2011-07-01

Full Text Available Abstract Background As the supply of starch grain and sugar cane, currently the main feedstocks for bioethanol production, become limited, lignocelluloses will be sought as alternative materials for bioethanol production. Production of cellulosic ethanol is still cost-inefficient because of the low final ethanol concentration and the addition of nutrients. We report the use of simultaneous saccharification and cofermentation (SSCF of lignocellulosic residues from commercial furfural production (furfural residue, FR and corn kernels to compare different nutritional media. The final ethanol concentration, yield, number of live yeast cells, and yeast-cell death ratio were investigated to evaluate the effectiveness of integrating cellulosic and starch ethanol. Results Both the ethanol yield and number of live yeast cells increased with increasing corn-kernel concentration, whereas the yeast-cell death ratio decreased in SSCF of FR and corn kernels. An ethanol concentration of 73.1 g/L at 120 h, which corresponded to a 101.1% ethanol yield based on FR cellulose and corn starch, was obtained in SSCF of 7.5% FR and 14.5% corn kernels with mineral-salt medium. SSCF could simultaneously convert cellulose into ethanol from both corn kernels and FR, and SSCF ethanol yield was similar between the organic and mineral-salt media. Conclusions Starch ethanol promotes cellulosic ethanol by providing important nutrients for fermentative organisms, and in turn cellulosic ethanol promotes starch ethanol by providing cellulosic enzymes that convert the cellulosic polysaccharides in starch materials into additional ethanol. It is feasible to produce ethanol in SSCF of FR and corn kernels with mineral-salt medium. It would be cost-efficient to produce ethanol in SSCF of high concentrations of water-insoluble solids of lignocellulosic materials and corn kernels. Compared with prehydrolysis and fed-batch strategy using lignocellulosic materials, addition of starch

Phenology and biomass production of adapted and non-adapted tropical corn populations in Central Iowa

Science.gov (United States)

Biofuel production in the Midwestern United States has largely focused on corn (Zea mays L.) grain for ethanol production and more recently, corn stover for lignocellulosic ethanol. As an alternative to conventional corn, tropical corn populations have been evaluated. Tropical corn is the term used ...

Potential feedstock sources for ethanol production in Florida

Energy Technology Data Exchange (ETDEWEB)

Rahmani, Mohammad [Univ. of Florida, Gainesville, FL (United States); Hodges, Alan [Univ. of Florida, Gainesville, FL (United States)

2015-10-01

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

Ethanol production from corn cobs by co-culture of Saccharomyces ...

African Journals Online (AJOL)

Saccharomyces cerevisiae and Aspergillus niger were used in a co-culture for the simultaneous saccharification and fermentation (SSF) of 1% and 10% (w/v) dry pre-treated corn cobs to ethanol. Positive controls of glucose of same concentrations in a synthetic medium were also fermented. At 1% substrate concentration, ...

Production of ethanol and furfural from corn stover

Science.gov (United States)

Corn stover has potential for economical production of biofuels and value-added chemicals. The conversion of corn stover to sugars involves pretreatment and enzymatic hydrolysis. We have optimized hydrothermal, dilute H2SO4 and dilute H3PO4 pretreatments of corn stover for enzymatic saccharificati...

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

Directory of Open Access Journals (Sweden)

Bondesson Pia-Maria

2013-01-01

Full Text Available Abstract 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

Production of ethanol from cellulose (sawdust)

OpenAIRE

Otulugbu, Kingsley

2012-01-01

The production of ethanol from food such as corn, cassava etc. is the most predominate way of producing ethanol. This has led to a shortage in food, inbalance in food chain, increased food price and indirect land use. This thesis thus explores using another feed for the production of ethanol- hence ethanol from cellulose. Sawdust was used to carry out the experiment from the production of ethanol and two methods were considered: SHF (Separate Hydrolysis and Fermentation) and SSF (Simultaneous...

Determining the Cost of Producing Ethanol from Corn Starch and Lignocellulosic Feedstocks

Energy Technology Data Exchange (ETDEWEB)

McAloon, A.; Taylor, F.; Yee, W.; Ibsen, K.; Wooley, R.

2000-10-25

The mature corn-to-ethanol industry has many similarities to the emerging lignocellulose-to-ethanol industry. It is certainly possible that some of the early practitioners of this new technology will be the current corn ethanol producers. In order to begin to explore synergies between the two industries, a joint project between two agencies responsible for aiding these technologies in the Federal government was established. This joint project of the USDA-ARS and DOE/NREL looked at the two processes on a similar process design and engineering basis, and will eventually explore ways to combine them. This report describes the comparison of the processes, each producing 25 million annual gallons of fuel ethanol. This paper attempts to compare the two processes as mature technologies, which requires assuming that the technology improvements needed to make the lignocellulosic process commercializable are achieved, and enough plants have been built to make the design well-understood. Ass umptions about yield and design improvements possible from continued research were made for the emerging lignocellulose process. In order to compare the lignocellulose-to-ethanol process costs with the commercial corn-to-ethanol costs, it was assumed that the lignocellulose plant was an Nth generation plant, built after the industry had been sufficiently established to eliminate first-of-a-kind costs. This places the lignocellulose plant costs on a similar level with the current, established corn ethanol industry, whose costs are well known. The resulting costs of producing 25 million annual gallons of fuel ethanol from each process were determined. The figure below shows the production cost breakdown for each process. The largest cost contributor in the corn starch process is the feedstock; for the lignocellulosic process it is the capital cost, which is represented by depreciation cost on an annual basis.

Incorporating Agricultural Management Practices into the Assessment of Soil Carbon Change and Life-Cycle Greenhouse Gas Emissions of Corn Stover Ethanol Production

Energy Technology Data Exchange (ETDEWEB)

Qin, Zhangcai [Argonne National Lab. (ANL), Argonne, IL (United States); Canter, Christina E. [Argonne National Lab. (ANL), Argonne, IL (United States); Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); Mueller, Steffen [Univ. of Illinois, Chicago, IL (United States); Kwon, Ho-young [International Food Policy Research Inst., Washington, DC (United States); Han, Jeongwoo [Argonne National Lab. (ANL), Argonne, IL (United States); Wander, Michelle M. [Univ. of Illinois, Champaign, IL (United States); Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States)

2015-09-01

Land management practices such as cover crop adoption or manure application that can increase soil organic carbon (SOC) may provide a way to counter SOC loss upon removal of stover from corn fields for use as a biofuel feedstock. This report documents the data, methodology, and assumptions behind the incorporation of land management practices into corn-soybean systems that dominate U.S. grain production using varying levels of stover removal in the GREETTM (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) model and its CCLUB (Carbon Calculator for Land Use change from Biofuels production) module. Tillage (i.e., conventional, reduced and no tillage), corn stover removal (i.e., at 0, 30% and 60% removal rate), and organic matter input techniques (i.e., cover crop and manure application) are included in the analysis as major land management practices. Soil carbon changes associated with land management changes were modeled with a surrogate CENTURY model. The resulting SOC changes were incorporated into CCLUB while GREET was expanded to include energy and material consumption associated with cover crop adoption and manure application. Life-cycle greenhouse gas (GHG) emissions of stover ethanol were estimated using a marginal approach (all burdens and benefits assigned to corn stover ethanol) and an energy allocation approach (burdens and benefits divided between grain and stover ethanol). In the latter case, we considered corn grain and corn stover ethanol to be produced at an integrated facility. Life-cycle GHG emissions of corn stover ethanol are dependent upon the analysis approach selected (marginal versus allocation) and the land management techniques applied. The expansion of CCLUB and GREET to accommodate land management techniques can produce a wide range of results because users can select from multiple scenario options such as choosing tillage levels, stover removal rates, and whether crop yields increase annually or remain constant

Analysis of supply chain, scale factor, and optimum plant capacity for the production of ethanol from corn stover

International Nuclear Information System (INIS)

Leboreiro, Jose; Hilaly, Ahmad K.

2013-01-01

A detailed model is used to perform a thorough analysis on ethanol production from corn stover via the dilute acid process. The biomass supply chain cost model accounts for all steps needed to source corn stover including collection, transportation, and storage. The manufacturing cost model is based on work done at NREL; attainable conversions of key process parameters are used to calculate production cost. The choice of capital investment scaling function and scaling parameter has a significant impact on the optimum plant capacity. For the widely used exponential function, the scaling factors are functions of plant capacity. The pre-exponential factor decreases with increasing plant capacity while the exponential factor increases as the plant capacity increases. The use of scaling parameters calculated for small plant capacities leads to falsely large optimum plants; data from a wide range of plant capacities is required to produce accurate results. A mathematical expression to scale capital investment for fermentation-based biorefineries is proposed which accounts for the linear scaling behavior of bio-reactors (such as saccharification vessels and fermentors) as well as the exponential nature of all other plant equipment. Ignoring the linear scaling behavior of bio-reactors leads to artificially large optimum plant capacities. The minimum production cost is found to be in the range of 789–830 $ m −3 which is significantly higher than previously reported. Optimum plant capacities are in the range of 5750–9850 Mg d −1 . The optimum plant capacity and production cost are highly sensitive to farmer participation in biomass harvest for low participation rates. -- Highlights: •A detailed model is used to perform a technoeconomic analysis for the production of ethanol from corn stover. •The capital investment scaling factors were found to be a function of plant capacity. •Bio-reactors (such as saccharification vessels and fermentors) in large size

Evaluation of the multi-seeded (msd) mutant of sorghum for ethanol production

Science.gov (United States)

Grain sorghum [Sorghum bicolor (L.) Moench], a cost effective crop in semiarid regions, is an underestimated supplement to corn in starch based ethanol production. Twenty three multi-seeded (msd) mutant sorghums and one wild type sorghum BTx623 were evaluated for ethanol production and effect of che...

How does petroleum price and corn yield volatility affect ethanol markets with and without an ethanol use mandate?

International Nuclear Information System (INIS)

Thompson, Wyatt; Meyer, Seth; Westhoff, Pat

2009-01-01

The recent increase in ethanol use in the US strengthens and changes the nature of links between agricultural and energy markets. Here, we explore the interaction of market volatility and the scope for policy to affect this interaction, with a focus on how corn yields and petroleum prices affect ethanol prices. Mandates associated with new US energy legislation may intervene in these links in the medium-term future. We simulate stochastically a structural model that represents these markets, and that includes mandates, in order to assess how shocks to corn or oil markets can affect ethanol price and use. We estimate that the mandate makes ethanol producer prices more sensitive to corn yields and less sensitive to changes in petroleum prices overall. We note a discontinuity in these links that is caused by the mandate. Ethanol use can exceed the mandate if petroleum prices and corn yields are high enough, but the mandate limits downside adjustments in ethanol use to low petroleum prices or corn yields

Design and analysis of fuel ethanol production from raw glycerol

International Nuclear Information System (INIS)

Posada, J.A.; Cardona, C.A.

2010-01-01

Three configurations for fuel ethanol production from raw glycerol using Escherichia coli were simulated and economically assessed using Aspen Plus and Aspen Icarus, respectively. These assessments considered raw glycerol (60 wt%) purification to both crude glycerol (88 wt%) and pure glycerol (98 wt%). The highest purification cost (PC) was obtained using pure glycerol due to its higher energy consumption in the distillation stage. In addition, the remaining methanol in the raw glycerol stream was recovered and recycled, decreasing the purification costs. The E. coli strain is able to convert crude glycerol (at 10 g/L or 20 g/L), or pure glycerol (at 10 g/L) to ethanol. Among these three glycerol concentrations, the lowest bioconversion cost was obtained when crude glycerol was diluted at 20 g/L. Purification and global production costs were compared with the commercial prices of glycerol and fuel ethanol from corn and sugarcane. Purification costs of raw glycerol were lower than previously reported values due to the methanol recovery. Global production costs for fuel ethanol from glycerol were lower than the reported values for corn-based production and higher than those for cane-based production. (author)

Fuel ethanol production from granular corn starch using Saccharomyces cerevisiae in a long term repeated SSF process with full stillage recycling.

Science.gov (United States)

Białas, Wojciech; Szymanowska, Daria; Grajek, Włodzimierz

2010-05-01

A major problem with fermentative ethanol production is the formation of large amounts of numerous organic pollutants. In an industrial distillery, stillage, fermenter and condenser cooling water are the main sources of wastewater. However, the selection of a proper technology makes it possible to almost completely avoid emissions of such kind of wastewater to the environment. This study examines the effect of stillage recirculation on fuel ethanol production. It is based on the use of Saccharomyces cerevisiae and a granular starch hydrolyzing enzyme in a simultaneous saccharification and fermentation process using a native starch obtained from corn flour. It was shown that the yield of the ethanol production was not influenced by the recycled stillage, a mean yield being 83.38% of the theoretical value. No significant trend for change in the ethanol concentration or in the residual starch was observed during any particular run, even after the 75% of fresh water was replaced with stillage. Thus, by applying this new clean technology it is possible to significantly reduce the rate of water consumption and in this way the production of by-products such as stillage. Copyright 2009 Elsevier Ltd. All rights reserved.

Biodiesel production from corn oil by transesterification process

International Nuclear Information System (INIS)

Khan, N.A.; Dessouky, H.

2009-01-01

There is much political demand and economic pressure to convert agricultural surpluses into material, such as motor fuel, in which the world is deficient. Transport industry is primary consumer of crude oil. Due to scarcity of known petroleum reserves, the possible alternative fuel for use in present engine technology is biofuels. Europe, USA and Brazil are successfully using biofuels. Biofuels causes less environmental pollution as compared to normal petro fuels. As a fuel, ethanol (gasohol) is used in internal combustion engine while methyester (Biodiesel) is used in diesel engines with same or better performance as compared to petro fuels. Corn is very valuable crop with numerous industrial applications, and is used in more than 300 modern industries, including the manufacture of textiles, paper, adhesives, insecticides, paints, soaps, explosives and many more. Presently the biggest source of ethanol production is from corn (produced by USA). Edible oil can also be extracted from corn which is normally used for cooking and it can be used for biodiesel production. Many countries are experimenting on fats and oil to get feasible data for production of biodiesel. Presently USA prefer to use soybean oil as raw material for commercial production of biodiesel while in Europe rapeseed oil is preferred, so therefore, it depends upon the availability of raw material in particular area and may change from location to location. In Pakistan we started with corn oil to produce biodiesel by transesterification method. In present study different design parameters such as effect of temperature, catalyst concentration, molar ratio, and Stirrer speed were founded for better conversion of neat and used corn oil into biodiesel. The optimum parameters proposed for neat corn oil are 0.5% of catalyst based on weight of corn oil, temperature between 50 deg. C to 60 deg. C, reaction time 15 minutes, molar ratio of 6:1 and speed of stirrer 155 rpm. In case of used corn oil high catalyst

Exploring Corn-Ethanol As A Complex Problem To Teach Sustainability Concepts Across The Science-Business-Liberal Arts Curriculum

Science.gov (United States)

Oches, E. A.; Szymanski, D. W.; Snyder, B.; Gulati, G. J.; Davis, P. T.

2012-12-01

stakeholders in developing and implementing policy on renewable fuels standards and ethanol production targets for the U.S. In Microeconomics students learn cost-benefit analysis and other concepts by applying economics principles to the corn ethanol problem. Following the disciplinary activities, students are asked to reconsider the central corn ethanol problem and evaluate it from a sustainability perspective. Assessment is ongoing, although initial results suggest that undergraduate students have difficulty integrating knowledge across multiple disciplines when evaluating a complex sustainability problem. Based on our initial assessment, we are exploring ways to modify the corn ethanol module as well as fine-tune the assessment instruments to provide the most effective outcomes possible. Because there are commonly institutional barriers to team teaching and other methods of cross-disciplinary instruction, we are recruiting faculty from additional disciplines to adapt and implement the corn ethanol module as a way of integrating sustainability concepts across the curriculum. Our goal is to teach complex, trans-disciplinary problem-solving and have students explore ways in which sustainability issues must be addressed through the application of concepts from the environmental and social sciences, public policy, and economics.

Ethanol production in a membrane bioreactor: pilot-scale trials in a corn wet mill.

Science.gov (United States)

Escobar, J M; Rane, K D; Cheryan, M

2001-01-01

Pilot plant trials were conducted in a corn wet mill with a 7000-L membrane recycle bioreactor (MRB) that integrated ceramic microfiltration membranes in a semi-closed loop configuration with a stirred-tank reactor. Residence times of 7.5-10 h with ethanol outputs of 10-11.5% (v/v) were obtained when the cell concentration was 60-100 g/L dry wt of yeast, equivalent to about 10(9)-10(10) cells/mL. The performance of the membrane was dependent on the startup mode and pressure management techniques. A steady flux of 70 L/(m2 x h) could be maintained for several days before cleaning was necessary. The benefits of the MRB include better productivity; a clear product stream containing no particulates or yeast cells, which should improve subsequent stripping and distillation operations; and substantially reduced stillage handling. The capital cost of the MRB is $21-$34/(m3 x yr) ($0.08-$0.13/[gal x yr]) of ethanol capacity. Operating cost, including depreciation, energy, membrane replacement, maintenance, labor, and cleaning, is $4.5-9/m3 ($0.017-$0.034/gal) of ethanol.

Ethanol and agriculture: Effect of increased production on crop and livestock sectors. Agricultural economic report

International Nuclear Information System (INIS)

House, R.; Peters, M.; Baumes, H.; Disney, W.T.

1993-05-01

Expanded ethanol production could increase US farm income by as much as $1 billion (1.4 percent) by 2000. Because corn is the primary feedstock for ethanol, growers in the Corn Belt would benefit most from improved ethanol technology and heightened demand. Coproducts from the conversion process (corn gluten meal, corn gluten feed, and others) compete with soybean meal, soybean growers in the South may see revenues decline. The US balance of trade would improve with increased ethanol production as oil import needs decline

The effect of CO2 regulations on the cost of corn ethanol production

Science.gov (United States)

Plevin, R. J.; Mueller, S.

2008-04-01

To explore the effect of CO2 price on the effective cost of ethanol production we have developed a model that integrates financial and emissions accounting for dry-mill corn ethanol plants. Three policy options are modeled: (1) a charge per unit of life cycle CO2 emissions, (2) a charge per unit of direct biorefinery emissions only, and (3) a low carbon fuel standard (LCFS). A CO2 charge on life cycle emissions increases production costs by between 0.005 and 0.008 l-1 per 10 Mg-1 CO2 price increment, across all modeled plant energy systems, with increases under direct emissions somewhat lower in all cases. In contrast, a LCFS increases the cost of production for selected plant energy systems only: a LCFS requiring reductions in average fuel global warming intensity (GWI) with a target of 10% below the 2005 baseline increases the production costs for coal-fired plants only. For all other plant types, the LCFS operates as a subsidy. The findings depend strongly on the magnitude of a land use change adder. Some land use change adders currently discussed in the literature will push the GWI of all modeled production systems above the LCFS target, flipping the CO2 price from a subsidy to a tax.

Metabolic engineering of Escherichia coli for ethanol production without foreign genes

Science.gov (United States)

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

Long-run effects of falling cellulosic ethanol production costs on the US agricultural economy

International Nuclear Information System (INIS)

Campiche, Jody L; Bryant, Henry L; Richardson, James W

2010-01-01

Renewable energy production has been expanding at a rapid pace. New advances in cellulosic ethanol technologies have the potential to displace the use of petroleum as a transportation fuel, and could have significant effects on both the agricultural economy and the environment. In this letter, the effects of falling cellulosic ethanol production costs on the mix of ethanol feedstocks employed and on the US agricultural economy are examined. Results indicate that, as expected, cellulosic ethanol production increases by a substantial amount as conversion technology improves. Corn production increases initially following the introduction of cellulosic technology, because producers enjoy new revenue from sales of corn stover. After cellulosic ethanol production becomes substantially cheaper, however, acres are shifted from corn production to all other agricultural commodities. Essentially, this new technology could facilitate the exploitation of a previously under-employed resource (corn stover), resulting in an improvement in overall welfare. In the most optimistic scenario considered, 68% of US ethanol is derived from cellulosic sources, coarse grain production is reduced by about 2%, and the prices of all food commodities are reduced modestly.

Determining the Feasibility of Yellow Corn Production in Mexico

OpenAIRE

Mejia, Maria; Peel, Derrell S.

2009-01-01

Mexico produces large quantities of white corn for human consumption. Yellow corn production, mostly used for feed, has increased lately. Driving factors include higher domestic demand (growing livestock industry) and greater international demand (ethanol industry). This study uses enterprise budgeting to determine the feasibility of producing yellow corn in Mexico.

Impact of recycling stillage on conversion of dilute sulfuric acid pretreated corn stover to ethanol.

Science.gov (United States)

Mohagheghi, Ali; Schell, Daniel J

2010-04-01

Both the current corn starch to ethanol industry and the emerging lignocellulosic biofuels industry view recycling of spent fermentation broth or stillage as a method to reduce fresh water use. The objective of this study was to understand the impact of recycling stillage on conversion of corn stover to ethanol. Sugars in a dilute-acid pretreated corn stover hydrolysate were fermented to ethanol by the glucose-xylose fermenting bacteria Zymomonas mobilis 8b. Three serial fermentations were performed at two different initial sugar concentrations using either 10% or 25% of the stillage as makeup water for the next fermentation in the series. Serial fermentations were performed to achieve near steady state concentration of inhibitors and other compounds in the corn stover hydrolysate. Little impact on ethanol yields was seen at sugar concentrations equivalent to pretreated corn stover slurry at 15% (w/w) with 10% recycle of the stillage. However, ethanol yields became progressively poorer as the sugar concentration increased and fraction of the stillage recycled increased. At an equivalent corn stover slurry concentration of 20% with 25% recycled stillage the ethanol yield was only 5%. For this microorganism with dilute-acid pretreated corn stover, recycling a large fraction of the stillage had a significant negative impact on fermentation performance. Although this finding is of concern for biochemical-based lignocellulose conversion processes, other microorganism/pretreatment technology combinations will likely perform differently. (c) 2009 Wiley Periodicals, Inc.

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

Science.gov (United States)

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.

Monetary value of the environmental and health externalities associated with production of ethanol from biomass feedstocks

International Nuclear Information System (INIS)

Kusiima, Jamil M.; Powers, Susan E.

2010-01-01

This research is aimed at monetizing the life cycle environmental and health externalities associated with production of ethanol from corn, corn stover, switchgrass, and forest residue. The results of this study reveal current average external costs for the production of 1 l of ethanol ranged from $0.07 for forest residue to $0.57 for ethanol production from corn. Among the various feedstocks, the external costs of PM 10 , NO X , and PM 2.5 are among the greatest contributors to these costs. The combustion of fossil fuels in upstream fertilizer and energy production processes is the primary source of these emissions and their costs, especially for corn ethanol. The combined costs of emissions associated with the production and use of nitrogen fertilizer also contribute substantially to the net external costs. For cellulosic ethanol production, the combustion of waste lignin to generate heat and power helps to keep the external costs lower than corn ethanol. Credits both for the biogenic carbon combustion and displacement of grid electricity by exporting excess electricity substantially negate many of the emissions and external costs. External costs associated with greenhouse gas emissions were not significant. However, adding estimates of indirect GHG emissions from land use changes would nearly double corn ethanol cost estimates.

Enhanced bioprocessing of lignocellulose: Wood-rot fungal saccharification and fermentation of corn fiber to ethanol

Science.gov (United States)

Shrestha, Prachand

no improvement in ethanol yields. We showed that saccharification of lignocellulosic material with a wood-rot fungal process is quite feasible. Corn fiber from wet milling was best degraded to sugars using aerobic solid state fermentation with the soft-rot fungus T. reesei. However, it was shown that both the white-rot fungus P. chrysosporium and brown-rot fungus G. trabeum had the ability to produce additional consortia of hemi/cellulose degrading enzymes. It is likely that a consortium of enzymes from these fungi would be the best approach in saccharification of lignocellulose. In all cases, a subsequent anaerobic yeast process under submerged conditions is required to ferment the released sugars to ethanol. To our knowledge, this is the first time report on production of cellulolytic enzymes from wet-milled corn fiber using white- and brown-rot fungi for sequential fermentation of corn fiber hydrolyzate to ethanol. Keywords: lignocellulose, ethanol, biofuel, bioeconomy, biomass, renewable resources, corn fiber, pretreatment, solid-substrate fermentation, simultaneous saccharification and fermentation (SSF), white-rot fungus, brown-rot fungus, soft-rot fungus, fermentable sugars, enzyme activities, cellulytic enzymes Phanerochaete chrysosporium, Gloleophyllum trabeum, Trichoderma reesei, Saccharomyces cerevisiae.

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

Science.gov (United States)

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.

Replacing gasoline with corn ethanol results in significant environmental problem-shifting.

Science.gov (United States)

Yang, Yi; Bae, Junghan; Kim, Junbeum; Suh, Sangwon

2012-04-03

Previous studies on the life-cycle environmental impacts of corn ethanol and gasoline focused almost exclusively on energy balance and greenhouse gas (GHG) emissions and largely overlooked the influence of regional differences in agricultural practices. This study compares the environmental impact of gasoline and E85 taking into consideration 12 different environmental impacts and regional differences among 19 corn-growing states. Results show that E85 does not outperform gasoline when a wide spectrum of impacts is considered. If the impacts are aggregated using weights developed by the National Institute of Standards and Technology (NIST), overall, E85 generates approximately 6% to 108% (23% on average) greater impact compared with gasoline, depending on where corn is produced, primarily because corn production induces significant eutrophication impacts and requires intensive irrigation. If GHG emissions from the indirect land use changes are considered, the differences increase to between 16% and 118% (33% on average). Our study indicates that replacing gasoline with corn ethanol may only result in shifting the net environmental impacts primarily toward increased eutrophication and greater water scarcity. These results suggest that the environmental criteria used in the Energy Independence and Security Act (EISA) be re-evaluated to include additional categories of environmental impact beyond GHG emissions.

An evaluation of dilute acid and ammonia fiber explosion pretreatment for cellulosic ethanol production.

Science.gov (United States)

Mathew, Anil Kuruvilla; Parameshwaran, Binod; Sukumaran, Rajeev Kumar; Pandey, Ashok

2016-01-01

The challenge associated with cellulosic ethanol production is maximizing sugar yield at low cost. Current research is being focused to develop a pretreatment method to overcome biomass recalcitrance in an efficient way. This review is focused on two major pretreatments: dilute acid (DA) and ammonia fiber explosion (AFEX) pretreatment of corn stover and how these pretreatment cause morphological and chemical changes to corn stover in order to overcome the biomass recalcitrance. This review highlights the key differences of these two pretreatments based on compositional analysis, cellulose and its crystallinity, morphological changes, structural changes to lignin, enzymatic reactivity and enzyme adsorption onto pretreated solids and finally cellulosic ethanol production from the hydrolysate of DA and AFEX treated corn stover. Each stage of the process, AFEX pretreated corn stover was superior to DA treated corn stover. Copyright © 2015 Elsevier Ltd. All rights reserved.

Energy, carbon dioxide and water use implications of hydrous ethanol production

International Nuclear Information System (INIS)

Saffy, Howard A.; Northrop, William F.; Kittelson, David B.; Boies, Adam M.

2015-01-01

Highlights: • We use a chemical refinery model and exergy analysis to determine the impact of hydrous ethanol. • The process is 70% efficient with 86% of the losses from fermentation, steam generation and drying. • We found that producing 86 wt% ethanol is optimal for thermal energy consumption. • Hydrous ethanol production can reduce energy costs and emissions by ∼8%. • Hydrous ethanol reduces water use by decreasing evaporation in cooling towers. - Abstract: Sub-azeotropic hydrous ethanol has been demonstrated as an effective diesel fuel replacement when used in dual-fuel compression ignition engines. Previous studies have also suggested that hydrous ethanol may be more efficient to produce from corn than anhydrous ethanol. In this study, we investigate corn ethanol production from a dry-mill, natural gas-fired corn ethanol refinery, producing ethanol with a range of ethanol concentrations from 58 wt% to 100 wt% to determine the effect on energy use, water consumption and greenhouse gas (GHG) emissions in the refining stage of the corn ethanol lifecycle. A second law (exergy) analysis of anhydrous ethanol refining revealed the overall process to be 70% efficient, whereby 86% of the exergy losses could be accounted for by three processes: fermentation (34%), steam generation (29%) and distiller’s grains and solubles drying (23%). We found that producing 86 wt% ethanol is optimal as thermal energy consumption decreases by a maximum of 10% (from 7.7 MJ/L to 6.9 MJ/L). These savings have the potential to reduce energy costs by approximately 8% ($0.34/L) and reduce refinery emissions by 8% (2 g CO 2 e/MJ). Production of hydrous ethanol reduced refinery water use due to decreased evaporative losses in the cooling towers, leading to water savings of between 3% and 6% at 86 wt% ethanol.

Aspen Plus simulation of biomass integrated gasification combined cycle systems at corn ethanol plants

International Nuclear Information System (INIS)

Zheng, Huixiao; Kaliyan, Nalladurai; Morey, R. Vance

2013-01-01

Biomass integrated gasification combined cycle (BIGCC) systems and natural gas combined cycle (NGCC) systems are employed to provide heat and electricity to a 0.19 hm 3 y −1 (50 million gallon per year) corn ethanol plant using different fuels (syrup and corn stover, corn stover alone, and natural gas). Aspen Plus simulations of BIGCC/NGCC systems are performed to study effects of different fuels, gas turbine compression pressure, dryers (steam tube or superheated steam) for biomass fuels and ethanol co-products, and steam tube dryer exhaust treatment methods. The goal is to maximize electricity generation while meeting process heat needs of the plant. At fuel input rates of 110 MW, BIGCC systems with steam tube dryers provide 20–25 MW of power to the grid with system thermal efficiencies (net power generated plus process heat rate divided by fuel input rate) of 69–74%. NGCC systems with steam tube dryers provide 26–30 MW of power to the grid with system thermal efficiencies of 74–78%. BIGCC systems with superheated steam dryers provide 20–22 MW of power to the grid with system thermal efficiencies of 53–56%. The life-cycle greenhouse gas (GHG) emission reduction for conventional corn ethanol compared to gasoline is 39% for process heat with natural gas (grid electricity), 117% for BIGCC with syrup and corn stover fuel, 124% for BIGCC with corn stover fuel, and 93% for NGCC with natural gas fuel. These GHG emission estimates do not include indirect land use change effects. -- Highlights: •BIGCC and natural gas combined cycle systems at corn ethanol plants are simulated. •The best performance results in 25–30 MW power to grid. •The best performance results in 74–78% system thermal efficiencies. •GHG reduction for corn ethanol with BIGCC systems compared to gasoline is over 100%

Production of bioethanol from corn meal hydrolyzates

Energy Technology Data Exchange (ETDEWEB)

Ljiljana Mojovic; Svetlana Nikolic; Marica Rakin; Maja Vukasinovic [University of Belgrade, Belgrade (Serbia and Montenegro). Faculty of Technology and Metallurgy, Department of Biochemical Engineering and Biotechnology

2006-09-15

The two-step enzymatic hydrolysis of corn meal by commercially available {alpha}-amylase and glucoamylase and further ethanol fermentation of the obtained hydrolyzates by Saccharomyces cerevisiae yeast was studied. The conditions of starch hydrolysis such as substrate and enzyme concentration and the time required for enzymatic action were optimized taking into account both the effects of hydrolysis and ethanol fermentation. The corn meal hydrolyzates obtained were good substrates for ethanol fermentation by S. cerevisiae. The yield of ethanol of more than 80% (w/w) of the theoretical was achieved with a satisfactory volumetric productivity P (g/l h). No shortage of fermentable sugars was observed during simultaneous hydrolysis and fermentation. In this process, the savings in energy by carrying out the saccharification step at lower temperature (32{sup o}C) could be realized, as well as a reduction of the process time for 4 h. 31 refs., 5 figs., 2 tabs.

Technical and economical analyses of combined heat and power generation from distillers grains and corn stover in ethanol plants

International Nuclear Information System (INIS)

Wang, Lijun; Hanna, Milford A.; Weller, Curtis L.; Jones, David D.

2009-01-01

The technical and economical feasibilities of a novel integrated biomass gasification and fuel cell combined heat and power (CHP) system were analyzed for supplying heat and power in an ethanol plant from distillers grains (DG) and corn stover. In a current dry-grind plant with an annual production capacity of 189 million liters (50 million gallons) of ethanol, the energy cost for ethanol production using natural gas at a price of 6.47 US$/GJ for processing heat and commercial grid at a price of 0.062 US$/kWh for electrical power supply was 0.094 US$/liter. If the integrated CHP system using wet DG with 64.7% moisture on a wet basis at 105 US$/dry tonne and corn stover with 20% moisture at 30 US$/dry tonne as feedstock was used to supply heat and power in the ethanol plant, the energy costs for ethanol production would be 0.101 US$/liter and 0.070 US$/liter, which are 107% and 75% of the current energy cost for ethanol production, respectively. To meet the demand of processing heat and power in the ethanol plant, the integrated CHP system required 22.1 dry tonnes of corn stover with 20% moisture or 14.5 dry tonnes of DG with 64.7% moisture on a wet basis per hour, compared with the available 18.8 dry tonnes of DG per hour in the ethanol plant. High-value chemicals such as policosanols, phytosterols and free fatty acids can be extracted out of the raw DG to reduce the cost of DG as a feedstock of the integrated CHP system. The energy cost for ethanol production using the integrated CHP system with corn stover and DG as the feedstock for supplying heat and power can be reduced further by increasing ethanol production scale, decreasing the moisture content of biomass feedstock, and decreasing thermal energy to electricity output ratio of the CHP system. In terms of the energy efficiency of the integrated CHP system and the energy cost for ethanol production, the moisture content of the feedstock going into the integrated CHP should be lower than 70% on a wet basis

Techno-economic analysis of using corn stover to supply heat and power to a corn ethanol plant - Part 2: Cost of heat and power generation systems

International Nuclear Information System (INIS)

Mani, S.; Sokhansanj, S.; Tagore, S.; Turhollow, A.F.

2010-01-01

This paper presents a techno-economic analysis of corn stover fired process heating (PH) and the combined heat and power (CHP) generation systems for a typical corn ethanol plant (ethanol production capacity of 170 dam 3 ). Discounted cash flow method was used to estimate both the capital and operating costs of each system and compared with the existing natural gas fired heating system. Environmental impact assessment of using corn stover, coal and natural gas in the heat and/or power generation systems was also evaluated. Coal fired process heating (PH) system had the lowest annual operating cost due to the low fuel cost, but had the highest environmental and human toxicity impacts. The proposed combined heat and power (CHP) generation system required about 137 Gg of corn stover to generate 9.5 MW of electricity and 52.3 MW of process heat with an overall CHP efficiency of 83.3%. Stover fired CHP system would generate an annual savings of 3.6 M$ with an payback period of 6 y. Economics of the coal fired CHP system was very attractive compared to the stover fired CHP system due to lower fuel cost. But the greenhouse gas emissions per Mg of fuel for the coal fired CHP system was 32 times higher than that of stover fired CHP system. Corn stover fired heat and power generation system for a corn ethanol plant can improve the net energy balance and add environmental benefits to the corn to ethanol biorefinery.

Evaluation of corn germ from ethanol production as an alternative fat source in dairy cow diets.

Science.gov (United States)

Abdelqader, M M; Hippen, A R; Kalscheur, K F; Schingoethe, D J; Karges, K; Gibson, M L

2009-03-01

. Germ removed from corn grain before ethanol production provides an alternative source of fat for energy in lactating dairy cows when fed at 7 and 14% of diet DM. Our results suggest that fat from corn germ may be relatively protected with no adverse effect on DM intake, milk production, and milk composition when fed up to 14% of diet DM.

Pilot-scale submersed cultivation of R. microsporus var. oligosporus in thin stillage, a dry-grind corn-to-ethanol co-product

Science.gov (United States)

Erickson, Daniel Thomas

An innovative process to add value to a corn-to-ethanol co-product, Thin stillage, was studied for pilot-scale viability. A 1500L bioreactor was designed, operated, and optimized to cultivate Rhizopus microsporus var. oligosporus via submersed fermentation in Thin Stillage. The biomass was harvested and processed into a feed suitable for storage and ultimately for animal feeding trials. Characterization of the biomass and feed trials revealed that there is substantial potential as a nutrient dense feed supplement with 41.1% protein, 26.3% fat, and metabolizable energy on s dried basis. The amino acid profile is superior to that of DDGS, with most notably 1.7% Lys on dried basis. This process produces a significantly more nutrient dense product than DDGS, and could increase water-reclaimation in a dry-grind corn to ethanol plant. Industrially it would replace the energy intensive process of converting thin stillage into syrup that adds only $10-25/ton to DDG, while maintaining production of DDG. Using thin stillage as used a growth media for R. microsporus var. oligosporus, should not only lead to saving in energy costs, but also generate a high-value co-product which could lead to economic gains. Also there is still unexplored potential of enzymes, chitin, and co-culturing to further add value.

Fermentation of Acid-pretreated Corn Stover to Ethanol Without Detoxification Using Pichia stipitis

Science.gov (United States)

Agbogbo, Frank K.; Haagensen, Frank D.; Milam, David; Wenger, Kevin S.

In this work, the effect of adaptation on P. stipitis fermentation using acidpretreated corn stover hydrolyzates without detoxification was examined. Two different types of adaptation were employed, liquid hydrolyzate and solid state agar adaptation. Fermentation of 12.5% total solids undetoxified acid-pretreated corn stover was performed in shake flasks at different rotation speeds. At low rotation speed (100 rpm), both liquid hydrolyzate and solid agar adaptation highly improved the sugar consumption rate as well as ethanol production rate compared to the wild-type strains. The fermentation rate was higher for solid agar-adapted strains compared to liquid hydrolyzate-adapted strains. At a higher rotation speed (150 rpm), there was a faster sugar consumption and ethanol production for both the liquid-adapted and the wild-type strains. However, improvements in the fermentation rate between the liquid-adapted and wild strains were less pronounced at the high rotation speed.

Optimization of fermentation conditions for ethanol production from whey

Energy Technology Data Exchange (ETDEWEB)

Castillo, F J; Izaguirre, M F; Michelena, V; Moreno, B

1982-01-01

Optimal conditions for ethanol production in 7% whey solutions by the yeast Candida pseudotropicalis ATCC 8619 included an initial pH of 4.57 and 30 degrees. Complete fermentation of the available lactose took place without supplementary nutrients; additions of N and P salts, yeast extract, or corn steep liquor resulted in increased yeast production and lower ethanol yields. A possible correlation was observed between increases in yeast inocula and lactose utilization and ethanol production rates; 8.35 g ethanol/L was obtained within 22 hours by using a yeast inoculum of 13.9 g/L. No differences in fermentation rates or ethanol yields were observed when whole or deproteinized whey solutions were used. Concentrated whey permeates, obtained after removal of the valuable proteins from whey, can be effectively fermented for ethanol production.

Subnational mobility and consumption-based environmental accounting of US corn in animal protein and ethanol supply chains

Science.gov (United States)

Smith, Timothy M.; Kim, Taegon; Pelton, Rylie E. O.; Suh, Kyo; Schmitt, Jennifer

2017-01-01

Corn production, and its associated inputs, is a relatively large source of greenhouse gas emissions and uses significant amounts of water and land, thus contributing to climate change, fossil fuel depletion, local air pollutants, and local water scarcity. As large consumers of this corn, corporations in the ethanol and animal protein industries are increasingly assessing and reporting sustainability impacts across their supply chains to identify, prioritize, and communicate sustainability risks and opportunities material to their operations. In doing so, many have discovered that the direct impacts of their owned operations are dwarfed by those upstream in the supply chain, requiring transparency and knowledge about environmental impacts along the supply chains. Life cycle assessments (LCAs) have been used to identify hotspots of environmental impacts at national levels, yet these provide little subnational information necessary for guiding firms’ specific supply networks. In this paper, our Food System Supply-Chain Sustainability (FoodS3) model connects spatial, firm-specific demand of corn purchasers with upstream corn production in the United States through a cost minimization transport model. This provides a means to link county-level corn production in the United States to firm-specific demand locations associated with downstream processing facilities. Our model substantially improves current LCA assessment efforts that are confined to broad national or state level impacts. In drilling down to subnational levels of environmental impacts that occur over heterogeneous areas and aggregating these landscape impacts by specific supply networks, targeted opportunities for improvements to the sustainability performance of supply chains are identified. PMID:28874548

Subnational mobility and consumption-based environmental accounting of US corn in animal protein and ethanol supply chains.

Science.gov (United States)

Smith, Timothy M; Goodkind, Andrew L; Kim, Taegon; Pelton, Rylie E O; Suh, Kyo; Schmitt, Jennifer

2017-09-19

Corn production, and its associated inputs, is a relatively large source of greenhouse gas emissions and uses significant amounts of water and land, thus contributing to climate change, fossil fuel depletion, local air pollutants, and local water scarcity. As large consumers of this corn, corporations in the ethanol and animal protein industries are increasingly assessing and reporting sustainability impacts across their supply chains to identify, prioritize, and communicate sustainability risks and opportunities material to their operations. In doing so, many have discovered that the direct impacts of their owned operations are dwarfed by those upstream in the supply chain, requiring transparency and knowledge about environmental impacts along the supply chains. Life cycle assessments (LCAs) have been used to identify hotspots of environmental impacts at national levels, yet these provide little subnational information necessary for guiding firms' specific supply networks. In this paper, our Food System Supply-Chain Sustainability (FoodS 3 ) model connects spatial, firm-specific demand of corn purchasers with upstream corn production in the United States through a cost minimization transport model. This provides a means to link county-level corn production in the United States to firm-specific demand locations associated with downstream processing facilities. Our model substantially improves current LCA assessment efforts that are confined to broad national or state level impacts. In drilling down to subnational levels of environmental impacts that occur over heterogeneous areas and aggregating these landscape impacts by specific supply networks, targeted opportunities for improvements to the sustainability performance of supply chains are identified.

Bio-butanol vs. bio-ethanol: A technical and economic assessment for corn and switchgrass fermented by yeast or Clostridium acetobutylicum

International Nuclear Information System (INIS)

Pfromm, Peter H.; Amanor-Boadu, Vincent; Nelson, Richard; Vadlani, Praveen; Madl, Ronald

2010-01-01

Fermentation-derived butanol is a possible alternative to ethanol as a fungible biomass-based liquid transportation fuel. We compare the fermentation-based production of n-butanol vs. ethanol from corn or switchgrass through the liquid fuel yield in terms of the lower heating value (LHV). Industrial scale data on fermentation to n-butanol (ABE fermentation) or ethanol (yeast) establishes a baseline at this time, and puts recent advances in fermentation to butanol in perspective. A dynamic simulation demonstrates the technical, economic and policy implications. The energy yield of n-butanol is about half that of ethanol from corn or switchgrass using current ABE technology. This is a serious disadvantage for n-butanol since feedstock costs are a significant portion of the fuel price. Low yield increases n-butanol's life-cycle greenhouse gas emission for the same amount of LHV compared to ethanol. A given fermenter volume can produce only about one quarter of the LHV as n-butanol per unit time compared to ethanol. This increases capital costs. The sometimes touted advantage of n-butanol being more compatible with existing pipelines is, according to our techno-economic simulations insufficient to alter the conclusion because of the capital costs to connect plants via pipeline.

Water consumption in the production of ethanol and petroleum gasoline.

Science.gov (United States)

Wu, May; Mintz, Marianne; Wang, Michael; Arora, Salil

2009-11-01

We assessed current water consumption during liquid fuel production, evaluating major steps of fuel lifecycle for five fuel pathways: bioethanol from corn, bioethanol from cellulosic feedstocks, gasoline from U.S. conventional crude obtained from onshore wells, gasoline from Saudi Arabian crude, and gasoline from Canadian oil sands. Our analysis revealed that the amount of irrigation water used to grow biofuel feedstocks varies significantly from one region to another and that water consumption for biofuel production varies with processing technology. In oil exploration and production, water consumption depends on the source and location of crude, the recovery technology, and the amount of produced water re-injected for oil recovery. Our results also indicate that crop irrigation is the most important factor determining water consumption in the production of corn ethanol. Nearly 70% of U.S. corn used for ethanol is produced in regions where 10-17 liters of water are consumed to produce one liter of ethanol. Ethanol production plants are less water intensive and there is a downward trend in water consumption. Water requirements for switchgrass ethanol production vary from 1.9 to 9.8 liters for each liter of ethanol produced. We found that water is consumed at a rate of 2.8-6.6 liters for each liter of gasoline produced for more than 90% of crude oil obtained from conventional onshore sources in the U.S. and more than half of crude oil imported from Saudi Arabia. For more than 55% of crude oil from Canadian oil sands, about 5.2 liters of water are consumed for each liter of gasoline produced. Our analysis highlighted the vital importance of water management during the feedstock production and conversion stage of the fuel lifecycle.

Water Consumption in the Production of Ethanol and Petroleum Gasoline

Science.gov (United States)

Wu, May; Mintz, Marianne; Wang, Michael; Arora, Salil

2009-11-01

We assessed current water consumption during liquid fuel production, evaluating major steps of fuel lifecycle for five fuel pathways: bioethanol from corn, bioethanol from cellulosic feedstocks, gasoline from U.S. conventional crude obtained from onshore wells, gasoline from Saudi Arabian crude, and gasoline from Canadian oil sands. Our analysis revealed that the amount of irrigation water used to grow biofuel feedstocks varies significantly from one region to another and that water consumption for biofuel production varies with processing technology. In oil exploration and production, water consumption depends on the source and location of crude, the recovery technology, and the amount of produced water re-injected for oil recovery. Our results also indicate that crop irrigation is the most important factor determining water consumption in the production of corn ethanol. Nearly 70% of U.S. corn used for ethanol is produced in regions where 10-17 liters of water are consumed to produce one liter of ethanol. Ethanol production plants are less water intensive and there is a downward trend in water consumption. Water requirements for switchgrass ethanol production vary from 1.9 to 9.8 liters for each liter of ethanol produced. We found that water is consumed at a rate of 2.8-6.6 liters for each liter of gasoline produced for more than 90% of crude oil obtained from conventional onshore sources in the U.S. and more than half of crude oil imported from Saudi Arabia. For more than 55% of crude oil from Canadian oil sands, about 5.2 liters of water are consumed for each liter of gasoline produced. Our analysis highlighted the vital importance of water management during the feedstock production and conversion stage of the fuel lifecycle.

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

Science.gov (United States)

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

High ethanol yields using Aspergillus oryzae koji and corn media

Energy Technology Data Exchange (ETDEWEB)

Ziffer, J.; Iosif, M.C.

1982-01-01

High ethanol and stillage solids were achieved using whole corn mashes. Ethanol yields of 14% (98.5% of theory) and stillage levels of approximately 23% were obtained in 74-90 hours using mild acid pretreatment with A. oryzae wheat bran koji saccharification. High ethanol yields were also obtained with bacterial amylase, instead of the acid treatment, when the sterilization step was omitted. The implications of ethanol fermentation process modifications are explored.

Influence of different SSF conditions on ethanol production from corn stover at high solids loadings

DEFF Research Database (Denmark)

Gladis, Arne; Bondesson, Pia-Maria; Galbe, Mats

2015-01-01

In this study, three different kinds of simultaneous saccharification and fermentation (SSF) of washed pretreated corn stover with water-insoluble solids (WIS) content of 20% were investigated to find which one resulted in highest ethanol yield at high-solids loadings. The different methods were...

An Indirect Route for Ethanol Production

Energy Technology Data Exchange (ETDEWEB)

Eggeman, T.; Verser, D.; Weber, E.

2005-04-29

The ZeaChem indirect method is a radically new approach to producing fuel ethanol from renewable resources. Sugar and syngas processing platforms are combined in a novel way that allows all fractions of biomass feedstocks (e.g. carbohydrates, lignins, etc.) to contribute their energy directly into the ethanol product via fermentation and hydrogen based chemical process technologies. The goals of this project were: (1) Collect engineering data necessary for scale-up of the indirect route for ethanol production, and (2) Produce process and economic models to guide the development effort. Both goals were successfully accomplished. The projected economics of the Base Case developed in this work are comparable to today's corn based ethanol technology. Sensitivity analysis shows that significant improvements in economics for the indirect route would result if a biomass feedstock rather that starch hydrolyzate were used as the carbohydrate source. The energy ratio, defined as the ratio of green energy produced divided by the amount of fossil energy consumed, is projected to be 3.11 to 12.32 for the indirect route depending upon the details of implementation. Conventional technology has an energy ratio of 1.34, thus the indirect route will have a significant environmental advantage over today's technology. Energy savings of 7.48 trillion Btu/yr will result when 100 MMgal/yr (neat) of ethanol capacity via the indirect route is placed on-line by the year 2010.

Fuel ethanol production from lignocellulose: a challenge for metabolic engineering and process integration

DEFF Research Database (Denmark)

Zaldivar, Jesus; Nielsen, Jens; Olsson, Lisbeth

2001-01-01

and with the implementation of environmental protection laws in many countries, demand for this fuel is increasing. Efficient ethanol production processes and cheap substrates are needed. Current ethanol production processes using crops such as sugar cane and corn are well-established; however, utilization of a cheaper...... substrate such as lignocellulose could make bioethanol more competitive with fossil fuel. The processing and utilization of this substrate is complex, differing, in many aspects from crop-based ethanol production. One important requirement is an efficient microorganism able to ferment a variety of sugars......With industrial development growing rapidly, there is a need for environmentally sustainable energy sources. Bioethanol (ethanol from biomass) is an attractive, sustainable energy source to fuel transportation. Based on the premise that fuel bioethanol can contribute to a cleaner environment...

Feasibility of converting a sugar beet plant to fuel ethanol production

Energy Technology Data Exchange (ETDEWEB)

Hammaker, G S; Pfost, H B; David, M L; Marino, M L

1981-04-01

This study was performed to assess the feasibility of producing fuel ethanol from sugar beets. Sugar beets are a major agricultural crop in the area and the beet sugar industry is a major employer. There have been some indications that increasing competition from imported sugar and fructose sugar produced from corn may lead to lower average sugar prices than have prevailed in the past. Fuel ethanol might provide an attractive alternative market for beets and ethanol production would continue to provide an industrial base for labor. Ethanol production from beets would utilize much of the same field and plant equipment as is now used for sugar. It is logical to examine the modification of an existing sugar plant from producing sugar to ethanol. The decision was made to use Great Western Sugar Company's plant at Mitchell as the example plant. This plant was selected primarily on the basis of its independence from other plants and the availability of relatively nearby beet acreage. The potential feedstocks assessed included sugar beets, corn, hybrid beets, and potatoes. Markets were assessed for ethanol and fermentation by-products saleability. Investment and operating costs were determined for each prospective plant. Plants were evaluated using a discounted cash flow technique to obtain data on full production costs. Environmental, health, safety, and socio-economic aspects of potential facilities were examined. Three consulting engineering firms and 3 engineering-construction firms are considered capable of providing the desired turn-key engineering design and construction services. It was concluded that the project is technically feasible. (DMC)

Characterization of very high gravity ethanol fermentation of corn mash. Effect of glucoamylase dosage, pre-saccharification and yeast strain

DEFF Research Database (Denmark)

Devantier, Rasmus; Pedersen, S; Olsson, Lisbeth

2005-01-01

Ethanol was produced from very high gravity mashes of dry milled corn (35% w/w total dry matter) under simultaneous saccharification and fermentation conditions. The effects of glucoamylase dosage, pre-saccharification and Saccharomyces cerevisiae strain on the growth characteristics such as the ......Ethanol was produced from very high gravity mashes of dry milled corn (35% w/w total dry matter) under simultaneous saccharification and fermentation conditions. The effects of glucoamylase dosage, pre-saccharification and Saccharomyces cerevisiae strain on the growth characteristics...... such as the ethanol yield and volumetric and specific productivity were determined. It was shown that higher glucoamylase doses and/or pre-saccharification accelerated the simultaneous saccharification and fermentation process and increased the final ethanol concentration from 106 to 126 g/kg although the maximal...... specific growth rate was decreased. Ethanol production was not only growth related, as more than half of the total saccharides were consumed and more than half of the ethanol was produced during the stationary phase. Furthermore, a high stress tolerance of the applied yeast strain was found to be crucial...

Evaluation of continuous ethanol fermentation of dilute-acid corn stover hydrolysate using thermophilic anaerobic bacterium Thermoanaerobacter BG1L1

DEFF Research Database (Denmark)

Georgieva, Tania I.; Ahring, Birgitte Kiær

2007-01-01

Dilute sulfuric acid pretreated corn stover is potential feedstock of industrial interest for second generation fuel ethanol production. However, the toxicity of corn stover hydrolysate (PCS) has been a challenge for fermentation by recombinant xylose fermenting organisms. In this work...

Improvement of enzymatic hydrolysis and ethanol production from corn stalk by alkali and N-methylmorpholine-N-oxide pretreatments.

Science.gov (United States)

Cai, Ling-Yan; Ma, Yu-Long; Ma, Xiao-Xia; Lv, Jun-Min

2016-07-01

A combinative technology of alkali and N-methylmorpholine-N-oxide (NMMO) was used to pretreat corn stalk (CS) for improving the efficiencies of subsequent enzymatic hydrolysis and ethanol fermentation. The results showed that this strategy could not only remove hemicellulose and lignin but also decrease the crystallinity of cellulose. About 98.0% of enzymatic hydrolysis yield was obtained from the pretreated CS as compared with 46.9% from the untreated sample. The yield for corresponding ethanol yield was 64.6% while untreated CS was only 18.8%. Besides, xylose yield obtained from the untreated CS was only 11.1%, while this value was 93.8% for alkali with NMMO pretreated sample. These results suggest that a combination of alkali with 50% (wt/wt) NMMO solution may be a promising alternative for pretreatment of lignocellulose, which can increase the productions of subsequent enzymatic hydrolysis and ethanol fermentation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Amylolysis of raw corn by Aspergillus niger for simultaneous ethanol fermentation

Energy Technology Data Exchange (ETDEWEB)

Han, I.Y.; Steinberg, M.P.

1987-01-01

The novelty of this approach was hydrolysis of the raw starch in ground corn to fermentable sugars that are simultaneously fermented to ethanol by yeast in a nonsterile environment. Thus, the conventional cooking step can be eliminated for energy conservation. A koji of Aspergillus niger grown on whole corn for 3 days was the crude enzyme source. A ratio of 0.2 g dry koji/g total solids was found sufficient. Optimum pH was 4.2. Ethanol concentration was 7.7% (w/w) in the aqueous phase with 92% raw starch conversion. Agitation increased rate. Sacharification was the rate-limiting step. The initial ethanol concentration preventing fermentation was estimated to be 8.3% by weight. (Refs. 96).

Physiochemical Properties and Probiotic Survivability of Symbiotic Corn-Based Yogurt-Like Product.

Science.gov (United States)

Wang, Cuina; Zheng, Huajie; Liu, Tingting; Wang, Dawei; Guo, Mingruo

2017-09-01

Corn is a major grain produced in northern China. Corn-based functional food products are very limited. In this study, a symbiotic corn-based yogurt-like product was developed. Corn milk was prepared through grinding, extrusion and milling, and hydration processes. Corn extrudate was prepared under the optimized conditions of corn flour particle size fermented at 35 °C for 6 h using a probiotic starter culture containing L. plantarum. Chemical composition (%) of the symbiotic corn-based yogurt-like product was: total solids (17.13 ± 0.31), protein (1.12 ± 0.03), fat (0.30 ± 0.05), carbohydrates (15.14 ± 0.19), and ash (0.16 ± 0.02), respectively. pH value of this symbiotic product decreased from 4.50 ± 0.03 to 3.88 ± 0.13 and the population of L. plantarum declined from 7.8 ± 0.09 to 7.1 ± 0.14 log CFU/mL during storage at 4 °C. SDS-PAGE analysis showed that there were no changes in protein profile during storage. Texture and consistency were also stable during the period of this study. It can be concluded that a set-type corn-based symbiotic yogurt-like product with good texture and stability was successfully developed that would be a good alternative to the dairy yogurt. © 2017 Institute of Food Technologists®.

Simultaneous saccharification and fermentation of alkaline-pretreated corn stover to ethanol using a recombinant yeast strain

Energy Technology Data Exchange (ETDEWEB)

Zhao, Jing; Xia, Liming [Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027 (China)

2009-10-15

Bio-ethanol converted from cheap and abundant lignocellulosic materials is a potential renewable resource to replace depleting fossil fuels. Simultaneous saccharification and fermentation (SSF) of alkaline-pretreated corn stover for the production of ethanol was investigated using a recombinant yeast strain Saccharomyces cerevisiae ZU-10. Low cellobiase activity in Trichoderma reesei cellulase resulted in cellobiose accumulation. Supplementing the simultaneous saccharification and fermentation system with cellobiase greatly reduced feedback inhibition caused by cellobiose to the cellulase reaction, thereby increased the ethanol yield. 12 h of enzymatic prehydrolysis at 50 C prior to simultaneous saccharification and fermentation was found to have a negative effect on the overall ethanol yield. Glucose and xylose produced from alkaline-pretreated corn stover could be co-fermented to ethanol effectively by S. cerevisiae ZU-10. An ethanol concentration of 27.8 g/L and the corresponding ethanol yield on carbohydrate in substrate of 0.350 g/g were achieved within 72 h at 33 C with 80 g/L of substrate and enzyme loadings of 20 filter paper activity units (FPU)/g substrate and 10 cellobiase units (CBU)/g substrate. The results are meaningful in co-conversion of cellulose and hemicellulose fraction of lignocellulosic materials to fuel ethanol. (author)

Microscopic Analysis of Corn Fiber Using Corn Starch- and Cellulose-Specific Molecular Probes

Energy Technology Data Exchange (ETDEWEB)

Porter, S. E.; Donohoe, B. S.; Beery, K. E.; Xu, Q.; Ding, S.-Y.; Vinzant, T. B.; Abbas, C. A.; Himmel, M. E.

2007-09-01

Ethanol is the primary liquid transportation fuel produced from renewable feedstocks in the United States today. The majority of corn grain, the primary feedstock for ethanol production, has been historically processed in wet mills yielding products such as gluten feed, gluten meal, starch, and germ. Starch extracted from the grain is used to produce ethanol in saccharification and fermentation steps; however the extraction of starch is not 100% efficient. To better understand starch extraction during the wet milling process, we have developed fluorescent probes that can be used to visually localize starch and cellulose in samples using confocal microscopy. These probes are based on the binding specificities of two types of carbohydrate binding modules (CBMs), which are small substrate-specific protein domains derived from carbohydrate degrading enzymes. CBMs were fused, using molecular cloning techniques, to a green fluorescent protein (GFP) or to the red fluorescent protein DsRed (RFP). Using these engineered probes, we found that the binding of the starch-specific probe correlates with starch content in corn fiber samples. We also demonstrate that there is starch internally localized in the endosperm that may contribute to the high starch content in corn fiber. We also surprisingly found that the cellulose-specific probe did not bind to most corn fiber samples, but only to corn fiber that had been hydrolyzed using a thermochemical process that removes the residual starch and much of the hemicellulose. Our findings should be of interest to those working to increase the efficiency of the corn grain to ethanol process.

NREL 2012 Achievement of Ethanol Cost Targets: Biochemical Ethanol Fermentation via Dilute-Acid Pretreatment and Enzymatic Hydrolysis of Corn Stover

Energy Technology Data Exchange (ETDEWEB)

Tao, L.; Schell, D.; Davis, R.; Tan, E.; Elander, R.; Bratis, A.

2014-04-01

For the DOE Bioenergy Technologies Office, the annual State of Technology (SOT) assessment is an essential activity for quantifying the benefits of biochemical platform research. This assessment has historically allowed the impact of research progress achieved through targeted Bioenergy Technologies Office funding to be quantified in terms of economic improvements within the context of a fully integrated cellulosic ethanol production process. As such, progress toward the ultimate 2012 goal of demonstrating cost-competitive cellulosic ethanol technology can be tracked. With an assumed feedstock cost for corn stover of $58.50/ton this target has historically been set at $1.41/gal ethanol for conversion costs only (exclusive of feedstock) and $2.15/gal total production cost (inclusive of feedstock) or minimum ethanol selling price (MESP). This year, fully integrated cellulosic ethanol production data generated by National Renewable Energy Laboratory (NREL) researchers in their Integrated Biorefinery Research Facility (IBRF) successfully demonstrated performance commensurate with both the FY 2012 SOT MESP target of $2.15/gal (2007$, $58.50/ton feedstock cost) and the conversion target of $1.41/gal through core research and process improvements in pretreatment, enzymatic hydrolysis, and fermentation.

Utilization of microwave and ultrasound pretreatments in the production of bioethanol from corn

Energy Technology Data Exchange (ETDEWEB)

Nikolic, Svetlana; Mojovic, Ljiljana; Rakin, Marica [University of Belgrade, Faculty of Technology and Metallurgy, Belgrade (Serbia); Pejin, Dusanka; Pejin, Jelena [University of Novi Sad, Faculty of Technology, Novi Sad (Serbia)

2011-08-15

Bioethanol production by simultaneous saccharification and fermentation (SSF) of corn meal by Saccharomyces cerevisiae var. ellipsoideus yeast in a batch system with prior ultrasound or microwave treatment was studied. The optimal duration of the pretreatments and the SSF process kinetics were assessed and determined. Also, the effect of ultrasound and microwave pretreatments on ethanol yield and productivity was investigated. An optimal duration of 5 min was determined for both pretreatments. Ultrasonic and microwave pretreatments effectively increased the glucose concentration obtained after liquefaction by 6.82 and 8.48%, respectively, compared to untreated control sample. Also, both pretreatments improved ethanol yield and productivity during the SSF process. Ultrasound and microwave pretreatments increased the maximum ethanol concentration produced in the SSF process by 11.15 and 13.40% (compared to the control sample), respectively. The application of microwave pretreatment resulted in higher glucose release during liquefaction and consequently in higher ethanol concentration, compared to ultrasound pretreatment. A maximum ethanol concentration of 9.91% (w/w) and percentage of theoretical ethanol yield of 92.27% were achieved after 44 h of the SSF process of corn meal with prior microwave treatment. (orig.)

Furfural and ethanol production from corn stover by dilute phosphoric acid pretreatment

Science.gov (United States)

Lignocellulosic biomass is the most abundant carbohydrate source in the world and has potential for economical production of biofuels, especially ethanol. However, its composition is an obstacle for the production of ethanol by the conventional ethanol producing yeast Saccharomyces cerevisiae as it...

Crude oil–corn–ethanol – nexus: A contextual approach

International Nuclear Information System (INIS)

Natanelov, Valeri; McKenzie, Andrew M.; Van Huylenbroeck, Guido

2013-01-01

This paper offers a holistic study on the complex relationships between crude oil, corn and ethanol during a turbulent period between 2006 and end of 2011. Through a holistic mapping of the current market situation and a contextual analytical design we show that there exists a strong relationship between crude oil and corn markets on one side, and crude oil and ethanol on the other. However, the price relationship between corn and ethanol was revealed to be less straightforward, and is driven by the US government fuel policy. Furthermore the study indicates that corn markets have became more prone to volatility due to ethanol production, especially when the demand for corn is high and/or the crude oil prices are high enough to create a competitive market for ethanol. - Highlights: • Strong relationship between crude oil–corn and crude oil–ethanol. • Corn–ethanol connected through a by-pass of crude oil markets. • Ethanol market has no direct impact on the price levels of corn. • Corn markets became more prone to volatility due to ethanol production

Quantifying Cradle-to-Farm Gate Life-Cycle Impacts Associated with Fertilizer used for Corn, Soybean, and Stover Production

Energy Technology Data Exchange (ETDEWEB)

Powers, S. E.

2005-05-01

Fertilizer use can cause environmental problems, particular eutrophication of water bodies from excess nitrogen or phosphorus. Increased fertilizer runoff is a concern for harvesting corn stover for ethanol production. This modeling study found that eutrophication potential for the base case already exceeds proposed water quality standards, that switching to no-till cultivation and collecting stover increased that eutrophication potential by 21%, and that switching to continuous-corn production on top of that would triple eutrophication potential.

Process Design and Economics for Biochemical Conversion of Lignocellulosic Biomass to Ethanol: Dilute-Acid Pretreatment and Enzymatic Hydrolysis of Corn Stover

Energy Technology Data Exchange (ETDEWEB)

Humbird, D.; Davis, R.; Tao, L.; Kinchin, C.; Hsu, D.; Aden, A.; Schoen, P.; Lukas, J.; Olthof, B.; Worley, M.; Sexton, D.; Dudgeon, D.

2011-03-01

This report describes one potential biochemical ethanol conversion process, conceptually based upon core conversion and process integration research at NREL. The overarching process design converts corn stover to ethanol by dilute-acid pretreatment, enzymatic saccharification, and co-fermentation. Building on design reports published in 2002 and 1999, NREL, together with the subcontractor Harris Group Inc., performed a complete review of the process design and economic model for the biomass-to-ethanol process. This update reflects NREL's current vision of the biochemical ethanol process and includes the latest research in the conversion areas (pretreatment, conditioning, saccharification, and fermentation), optimizations in product recovery, and our latest understanding of the ethanol plant's back end (wastewater and utilities). The conceptual design presented here reports ethanol production economics as determined by 2012 conversion targets and 'nth-plant' project costs and financing. For the biorefinery described here, processing 2,205 dry ton/day at 76% theoretical ethanol yield (79 gal/dry ton), the ethanol selling price is $2.15/gal in 2007$.

Bio-Ethanol Production from Poultry Manure

African Journals Online (AJOL)

john

ethanol. Fuel ethanol is known as bio-ethanol, since it is produced from plant materials by biological processes. Bioethanol is mainly produced by fermentation of sugar containing crops like corn, maize, wheat, sugar cane, sugar beet, potatoes, ...

Water reclamation and value-added animal feed from corn-ethanol stillage by fungal processing.

Science.gov (United States)

Rasmussen, M L; Khanal, S K; Pometto, A L; van Leeuwen, J Hans

2014-01-01

Rhizopus oligosporus was cultivated on thin stillage from a dry-grind corn ethanol plant. The aim of the research was to develop a process to replace the current energy-intensive flash evaporation and make use of this nutrient-rich stream to create a new co-product in the form of protein-rich biomass. Batch experiments in 5- and 50-L stirred bioreactors showed prolific fungal growth under non-sterile conditions. COD, suspended solids, glycerol, and organic acids removals, critical for in-plant water reuse, reached ca. 80%, 98%, 100% and 100%, respectively, within 5 d of fungal inoculation, enabling effluent recycle as process water. R. oligosporus contains 2% lysine, good levels of other essential amino acids, and 43% crude protein - a highly nutritious livestock feed. Avoiding water evaporation from thin stillage would furthermore save substantial energy inputs on corn ethanol plants. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

International Nuclear Information System (INIS)

Mangmeechai, Aweewan; Pavasant, Prasert

2013-01-01

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 only 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

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

Energy Technology Data Exchange (ETDEWEB)

Mangmeechai, Aweewan, E-mail: aweewan.m@nida.ac.th [National Institute of Development Administration, International College (Major in Public Policy and Management) (Thailand); Pavasant, Prasert [Chulalongkorn University, Department of Chemical Engineering, Faculty of Engineering (Thailand)

2013-12-15

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 only 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.

Utilization of corn residues for production of the polysaccharide schizophyllan

Science.gov (United States)

Abundant corn residues include fiber from wet milling operations and distillers' dried grains from dry grind ethanol plants. Biorefineries of the future will utilize such residues for the production of valuable bioproducts, particularly those traditionally produced from fossil fuels. Schizophyllan...

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

Science.gov (United States)

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

Influence of spatially dependent, modeled soil carbon emission factors on life-cycle greenhouse gas emissions of corn and cellulosic ethanol

Energy Technology Data Exchange (ETDEWEB)

Qin, Zhangcai [Energy Systems Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Dunn, Jennifer B. [Energy Systems Division, Argonne National Laboratory, 9700 South Cass Avenue Argonne IL 60439 USA; Kwon, Hoyoung [Environment and Production Technology Division, International Food Policy Research Institute, 2033 K St. NW Washington DC 20006 USA; Mueller, Steffen [Energy Resources Center, University of Illinois at Chicago, 1309 South Halsted Street Chicago IL 60607 USA; Wander, Michelle M. [Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign, 1102 South Goodwin Avenue Urbana IL 61801 USA

2016-03-03

Converting land to biofuel feedstock production incurs changes in soil organic carbon (SOC) that can influence biofuel life-cycle greenhouse gas (GHG) emissions. Estimates of these land use change (LUC) and life-cycle GHG emissions affect biofuels’ attractiveness and eligibility under a number of renewable fuel policies in the U.S. and abroad. Modeling was used to refine the spatial resolution and depth-extent of domestic estimates of SOC change for land (cropland, cropland pasture, grasslands, and forests) conversion scenarios to biofuel crops (corn, corn stover, switchgrass, Miscanthus, poplar, and willow). In most regions, conversions from cropland and cropland pasture to biofuel crops led to neutral or small levels of SOC sequestration, while conversion of grassland and forest generally caused net SOC loss. Results of SOC change were incorporated into the Greenhouse Gases, Regulated Emissions, and Energy use in Transportation (GREET) model to assess their influence on life-cycle GHG emissions for the biofuels considered. Total LUC GHG emissions (g CO2eq MJ-1) were 2.1–9.3 for corn, -0.7 for corn stover, -3.4–12.9 for switchgrass, and -20.1–-6.2 for Miscanthus; these varied with SOC modeling assumptions applied. Extending soil depth from 30 to 100cm affected spatially-explicit SOC change and overall LUC GHG emissions; however the influence on LUC GHG emissions estimates were less significant in corn and corn stover than cellulosic feedstocks. Total life-cycle GHG emissions (g CO2eq MJ-1, 100cm) were estimated to be 59–66 for corn ethanol, 14 for stover ethanol, 18-26 for switchgrass ethanol, and -0.6–-7 for Miscanthus ethanol.

The Energy Balance of Corn Ethanol: An Update

Energy Technology Data Exchange (ETDEWEB)

Shapouri, Hosein [United States Dept. of Agriculture (USDA), Washington DC (United States); Duffield, James A. [United States Dept. of Agriculture (USDA), Washington DC (United States); Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States)

2002-07-01

Studies conducted since the late 1970s have estimated the net energy value (NEV) of corn ethanol. However, variations in data and assumptions used among the studies have resulted in a wide range of estimates. This study identifies the factors causing this wide variation and develops a more consistent estimate.

Linking Air Land & Water to Examine the Vulnerability of Groundwater Nitrate Contamination from Increased Corn Production

Science.gov (United States)

The Renewable Fuel Standard (RFS) requires oil refiners to reach a target of 15 billion gallons of corn-based ethanol by 2022. However, there are concerns that the broad-scale use of corn as a source of ethanol may lead to unintended economic and environmental consequences. Thi...

Market for ethanol feed joint products

Energy Technology Data Exchange (ETDEWEB)

Hertzmark, D.; Gould, B.

1979-10-01

This report presents results of econometric estimations and mathematical simulations of markets for joint feed products of motor ethanol. The major issues considered are the nature of current market price relationships, effects on prices, including feed substitutes prices, and effects of demands for increased use of distillers' grains and gluten meal. The econometric section shows that soybean meal was by far the dominant force in the pricing of the two products. However, neither one could be adequately explained without the inclusion of corn in the estimating equations. Later research shows that this was due to the importance of both feeds for metabolizable energy as well as for protein in livestock diets. Current ration formulations would require some discounting of the value of the protein content of the two feeds. Careful siting of the ethanol facilities, and flexible design of the plants so that a maximum number of products may be extracted from the feedstock, seem necessary. Finally, the analysis indicates that substitution in animal diets of these joint products for the corn or milo used originally requires that additional energy be supplied to the animal by some type of forage crop. This implies that additional land may be required for energy production, for such marginal crops as hay and alfalfa, rather than for row crops.

Integrated Production of Xylonic Acid and Bioethanol from Acid-Catalyzed Steam-Exploded Corn Stover.

Science.gov (United States)

Zhu, Junjun; Rong, Yayun; Yang, Jinlong; Zhou, Xin; Xu, Yong; Zhang, Lingling; Chen, Jiahui; Yong, Qiang; Yu, Shiyuan

2015-07-01

High-efficiency xylose utilization is one of the restrictive factors of bioethanol industrialization. However, xylonic acid (XA) as a new bio-based platform chemical can be produced by oxidation of xylose with microbial. So, an applicable technology of XA bioconversion was integrated into the process of bioethanol production. After corn stover was pretreated with acid-catalyzed steam-explosion, solid and liquid fractions were obtained. The liquid fraction, also named as acid-catalyzed steam-exploded corn stover (ASC) prehydrolyzate (mainly containing xylose), was catalyzed with Gluconobacter oxydans NL71 to prepare XA. After 72 h of bioconversion of concentrated ASC prehydrolyzate (containing 55.0 g/L of xylose), the XA concentration reached a peak value of 54.97 g/L, the sugar utilization ratio and XA yield were 94.08 and 95.45 %, respectively. The solid fraction was hydrolyzed to produce glucose with cellulase and then fermented with Saccharomyces cerevisiae NL22 to produce ethanol. After 18 h of fermentation of concentrated enzymatic hydrolyzate (containing 86.22 g/L of glucose), the ethanol concentration reached its highest value of 41.48 g/L, the sugar utilization ratio and ethanol yield were 98.72 and 95.25 %, respectively. The mass balance showed that 1 t ethanol and 1.3 t XA were produced from 7.8 t oven dry corn stover.

Environmental aspects of eucalyptus based ethanol production and use

International Nuclear Information System (INIS)

González-García, Sara; Moreira, Ma. Teresa; Feijoo, Gumersindo

2012-01-01

A renewable biofuel economy is projected as a pathway to decrease dependence on fossil fuels as well as to reduce greenhouse gases (GHG) emissions. Ethanol produced on large-scale from lignocellulosic materials is considered the automotive fuel with the highest potential. In this paper, a life cycle assessment (LCA) study was developed to evaluate the environmental implications of the production of ethanol from a fast-growing short rotation crop (SRC): eucalyptus as well as its use in a flexi-fuel vehicle (FFV). The aim of the analysis was to assess the environmental performance of three ethanol based formulations: E10, E85 and E100, in comparison with conventional gasoline. The standard framework of LCA from International Standards Organization was followed and the system boundaries included the cultivation of the eucalyptus biomass, the processing to ethanol conversion, the blending with gasoline (when required) and the final use of fuels. The environmental results show reductions in all impact categories under assessment when shifting to ethanol based fuels, excluding photochemical oxidant formation, eutrophication as well as terrestrial and marine ecotoxicity which were considerably influenced by upstream activities related to ethanol manufacture. The LCA study remarked those stages where the researchers and technicians need to work to improve the environmental performance. Special attention must be paid on ethanol production related activities, such as on-site energy generation and distillation, as well as forest activities oriented to the biomass production. The use of forest machinery with higher efficiency levels, reduction of fertilizers dose and the control of diffuse emissions from the conversion plant would improve the environmental profile. -- Highlights: ► The identification of the environmental implications of the production and use of eucalyptus based ethanol was carried out. ► Eucalyptus is a Spanish common and abundant fast-growing short

A systems approach for the evaluation of ethanol production based on forages

Energy Technology Data Exchange (ETDEWEB)

Alvo, P. [McGill Univ., Ste. Anne de Bellevue, PQ (Canada). Macdonald Coll.; Savoie, P. [Agriculture and Agri-Food Canada, Quebec, PQ (Canada). Saine-Foy Research Centre; Tremblay, D. [Laval Univ., Quebec, PQ (Canada). Dept. de Genie Rural; Emond, J.-P.; Turcotte, G. [Laval Univ., Quebec City, PQ (Canada). Dept. de Sciences et Technologie des Aliments

1996-04-01

A systems approach is proposed to simultaneously consider the agronomic aspects of forage production and the processing aspects related to the extraction of a glucose or xylose substrate, its fermentation into ethanol and the optimal utilization of co-products (protein meal, fibrous residue). The energy to produce and transport forage on the farm was estimated to be only 375 MJ/t dry matter (DM) when liquid manure was used and 1165 MJ/t DM when mineral fertilizer was used. An additional 126 MJ/t DM would be required to transport it to a processing plant. In contrast, whole-plant corn production using mineral fertilizer required about 3211 MJ/t DM, but it had a potential ethanol yield 3.2 times greater per unit area than perennial forage. A forage system with mechanical juice extraction resulted in 8-20% of the original forage dry matter available in a liquid substrate with subsequent protein meal separation and the fermentation of soluble sugars into ethanol. Another forage system with relatively complete conversion of cellulose and hemicellulose into simple sugars by thermal, acidic and enzymatic treatments was estimated to produce 12-28 times more ethanol per unit area than the mechanically extracted juice. Complete conversion of perennial forages would meet the petroleum industry`s needs more consistently than simple extraction of soluble components. (Author)

Market penetration of ethanol

International Nuclear Information System (INIS)

Szulczyk, Kenneth R.; McCarl, Bruce A.; Cornforth, Gerald

2010-01-01

This research examines in detail the technology and economics of substituting ethanol for gasoline. This endeavor examines three issues. First, the benefits of ethanol/gasoline blends are examined, and then the technical problems of large-scale implementation of ethanol. Second, ethanol production possibilities are examined in detail from a variety of feedstocks and technologies. The feedstocks are the starch/sugar crops and crop residues, while the technologies are corn wet mill, dry grind, and lignocellulosic fermentation. Examining in detail the production possibilities allows the researchers to identity the extent of technological change, production costs, byproducts, and GHG emissions. Finally, a U.S. agricultural model, FASOMGHG, is updated which predicts the market penetration of ethanol given technological progress, variety of technologies and feedstocks, market interactions, energy prices, and GHG prices. FASOMGHG has several interesting results. First, gasoline prices have a small expansionary impact on the U.S. ethanol industry. Both agricultural producers' income and cost both increase with higher energy prices. If wholesale gasoline is $4 per gallon, the predicted ethanol market penetration attains 53% of U.S. gasoline consumption in 2030. Second, the corn wet mill remains an important industry for ethanol production, because this industry also produces corn oil, which could be converted to biodiesel. Third, GHG prices expand the ethanol industry. However, the GHG price expands the corn wet mill, but has an ambiguous impact on lignocellulosic ethanol. Feedstocks for lignocellulosic fermentation can also be burned with coal to generate electricity. Both industries are quite GHG efficient. Finally, U.S. government subsidies on biofuels have an expansionary impact on ethanol production, but may only increase market penetration by an additional 1% in 2030, which is approximately 6 billion gallons. (author)

Comparison of ethanol production from corn cobs and switchgrass following a pyrolysis-based biorefinery approach

NARCIS (Netherlands)

Luque, Luis; Oudenhoven, Stijn; Westerhof, Roel Johannes Maria; van Rossum, G.; Berruti, Franco; Kersten, Sascha R.A.; Rehmann, Lars

2016-01-01

Background One of the main obstacles in lignocellulosic ethanol production is the necessity of pretreatment and fractionation of the biomass feedstocks to produce sufficiently pure fermentable carbohydrates. In addition, the by-products (hemicellulose and lignin fraction) are of low value, when

A MICROWAVE-ASSISTED LIQUEFACTION AS A PRETREATMENT FOR THE BIOETHANOL PRODUCTION BY THE SIMULTANEOUS SACCHARIFICATION AND FERMENTATION OF CORN MEAL

Directory of Open Access Journals (Sweden)

Svetlana Nikolić

2008-11-01

Full Text Available A microwave-assisted liquefaction as a pretreatment for the bioethanol production by the simultaneous saccharification and fer entation (SSF of corn meal using Saccharomyces cerevisiae var. ellipsoideus yeast in a batch system was studied. An optimal power of microwaves of 80 W and the 5-min duration of the microwave treatment were selected by following the concentration of glucose released from the corn meal suspensions at hidromodul of 1:3 (corn meal to water ratio in the liquefaction step. The results indicated that the microwave pretreatment could increase the maximum ethanol concentration produced in the SSF process for 13.4 %. Consequently, a significant increase of the ethanol productivity on substrate (YP/S, as well as the volumetric ethanol productivity (P in this process, could be achieved

Sequential high gravity ethanol fermentation and anaerobic digestion of steam explosion and organosolv pretreated corn stover.

Science.gov (United States)

Katsimpouras, Constantinos; Zacharopoulou, Maria; Matsakas, Leonidas; Rova, Ulrika; Christakopoulos, Paul; Topakas, Evangelos

2017-11-01

The present work investigates the suitability of pretreated corn stover (CS) to serve as feedstock for high gravity (HG) ethanol production at solids-content of 24wt%. Steam explosion, with and without the addition of H 2 SO 4 , and organosolv pretreated CS samples underwent a liquefaction/saccharification step followed by simultaneous saccharification and fermentation (SSF). Maximum ethanol concentration of ca. 76g/L (78.3% ethanol yield) was obtained from steam exploded CS (SECS) with 0.2% H 2 SO 4 . Organosolv pretreated CS (OCS) also resulted in high ethanol concentration of ca. 65g/L (62.3% ethanol yield). Moreover, methane production through anaerobic digestion (AD) was conducted from fermentation residues and resulted in maximum methane yields of ca. 120 and 69mL/g volatile solids (VS) for SECS and OCS samples, respectively. The results indicated that the implementation of a liquefaction/saccharification step before SSF employing a liquefaction reactor seemed to handle HG conditions adequately. Copyright © 2017 Elsevier Ltd. All rights reserved.

High solid simultaneous saccharification and fermentation of wet oxidized corn stover to ethanol

DEFF Research Database (Denmark)

Varga, E.; Klinke, H.B.; Reczey, K.

2004-01-01

In this study ethanol was produced from corn stover pretreated by alkaline and acidic wet oxidation (WO) (195 degreesC, 15 min, 12 bar oxygen) followed by nonisothermal simultaneous saccharification and fermentation (SSF). In the first step of the SSF, small amounts of cellulases were added at 50...... increase of substrate concentration reduced the ethanol yield significant as a result of insufficient mass transfer. It was also shown that the fermentation could be followed with an easy monitoring system based on the weight loss of the produced CO2. (C) 2004 Wiley Periodicals, Inc....

Fuel-cycle assessment of selected bioethanol production

International Nuclear Information System (INIS)

Wu, M.; Wang, M.; Hong, H.

2007-01-01

A large amount of corn stover is available in the U.S. corn belt for the potential production of cellulosic bioethanol when the production technology becomes commercially ready. In fact, because corn stover is already available, it could serve as a starting point for producing cellulosic ethanol as a transportation fuel to help reduce the nation's demand for petroleum oil. Using the data available on the collection and transportation of corn stover and on the production of cellulosic ethanol, we have added the corn stover-to-ethanol pathway in the GREET model, a fuel-cycle model developed at Argonne National Laboratory. We then analyzed the life-cycle energy use and emission impacts of corn stover-derived fuel ethanol for use as E85 in flexible fuel vehicles (FFVs). The analysis included fertilizer manufacturing, corn farming, farming machinery manufacturing, stover collection and transportation, ethanol production, ethanol transportation, and ethanol use in light-duty vehicles (LDVs). Energy consumption of petroleum oil and fossil energy, emissions of greenhouse gases (carbon dioxide [CO 2 ], nitrous oxide [N 2 O], and methane [CH 4 ]), and emissions of criteria pollutants (carbon monoxide [CO], volatile organic compounds [VOCs], nitrogen oxide [NO x ], sulfur oxide [SO x ], and particulate matter with diameters smaller than 10 micrometers [PM 10 ]) during the fuel cycle were estimated. Scenarios of ethanol from corn grain, corn stover, and other cellulosic feedstocks were then compared with petroleum reformulated gasoline (RFG). Results showed that FFVs fueled with corn stover ethanol blends offer substantial energy savings (94-95%) relative to those fueled with RFG. For each Btu of corn stover ethanol produced and used, 0.09 Btu of fossil fuel is required. The cellulosic ethanol pathway avoids 86-89% of greenhouse gas emissions. Unlike the life cycle of corn grain-based ethanol, in which the ethanol plant consumes most of the fossil fuel, farming consumes most

Fuel-cycle assessment of selected bioethanol production.

Energy Technology Data Exchange (ETDEWEB)

Wu, M.; Wang, M.; Hong, H.; Energy Systems

2007-01-31

A large amount of corn stover is available in the U.S. corn belt for the potential production of cellulosic bioethanol when the production technology becomes commercially ready. In fact, because corn stover is already available, it could serve as a starting point for producing cellulosic ethanol as a transportation fuel to help reduce the nation's demand for petroleum oil. Using the data available on the collection and transportation of corn stover and on the production of cellulosic ethanol, we have added the corn stover-to-ethanol pathway in the GREET model, a fuel-cycle model developed at Argonne National Laboratory. We then analyzed the life-cycle energy use and emission impacts of corn stover-derived fuel ethanol for use as E85 in flexible fuel vehicles (FFVs). The analysis included fertilizer manufacturing, corn farming, farming machinery manufacturing, stover collection and transportation, ethanol production, ethanol transportation, and ethanol use in light-duty vehicles (LDVs). Energy consumption of petroleum oil and fossil energy, emissions of greenhouse gases (carbon dioxide [CO{sub 2}], nitrous oxide [N{sub 2}O], and methane [CH{sub 4}]), and emissions of criteria pollutants (carbon monoxide [CO], volatile organic compounds [VOCs], nitrogen oxide [NO{sub x}], sulfur oxide [SO{sub x}], and particulate matter with diameters smaller than 10 micrometers [PM{sub 10}]) during the fuel cycle were estimated. Scenarios of ethanol from corn grain, corn stover, and other cellulosic feedstocks were then compared with petroleum reformulated gasoline (RFG). Results showed that FFVs fueled with corn stover ethanol blends offer substantial energy savings (94-95%) relative to those fueled with RFG. For each Btu of corn stover ethanol produced and used, 0.09 Btu of fossil fuel is required. The cellulosic ethanol pathway avoids 86-89% of greenhouse gas emissions. Unlike the life cycle of corn grain-based ethanol, in which the ethanol plant consumes most of the fossil

Sugar-Based Ethanol Biorefinery: Ethanol, Succinic Acid and By-Product Production

Energy Technology Data Exchange (ETDEWEB)

Donal F. Day

2009-03-31

The work conducted in this project is an extension of the developments itemized in DE-FG-36-04GO14236. This program is designed to help the development of a biorefinery based around a raw sugar mill, which in Louisiana is an underutilized asset. Some technical questions were answered regarding the addition of a biomass to ethanol facility to existing sugar mills. The focus of this work is on developing technology to produce ethanol and valuable by-products from bagasse. Three major areas are addressed, feedstock storage, potential by-products and the technology for producing ethanol from dilute ammonia pre-treated bagasse. Sugar mills normally store bagasse in a simple pile. During the off season there is a natural degradation of the bagasse, due to the composting action of microorganisms in the pile. This has serious implications if bagasse must be stored to operate a bagasse/biorefinery for a 300+ day operating cycle. Deterioration of the fermentables in bagasse was found to be 6.5% per month, on pile storage. This indicates that long term storage of adequate amounts of bagasse for year-round operation is probably not feasible. Lignin from pretreatment seemed to offer a potential source of valuable by-products. Although a wide range of phenolic compounds were present in the effluent from dilute ammonia pretreatment, the concentrations of each (except for benzoic acid) were too low to consider for extraction. The cellulosic hydrolysis system was modified to produce commercially recoverable quantities of cellobiose, which has a small but growing market in the food process industries. A spin-off of this led to the production of a specific oligosaccharide which appears to have both medical and commercial implications as a fungal growth inhibitor. An alternate use of sugars produced from biomass hydrolysis would be to produce succinic acid as a chemical feedstock for other conversions. An organism was developed which can do this bioconversion, but the economics of

Environmental efficiency among corn ethanol plants

International Nuclear Information System (INIS)

Sesmero, Juan P.; Perrin, Richard K.; Fulginiti, Lilyan E.

2012-01-01

Economic viability of the US corn ethanol industry depends on prices, technical and economic efficiency of plants and the extent of policy support. Public policy support is tied to the environmental efficiency of plants measured as their impact on emissions of greenhouse gases. This study evaluates the environmental efficiency of seven recently constructed ethanol plants in the North Central region of the US, using nonparametric data envelopment analysis (DEA). The minimum feasible level of GHG emissions per unit of ethanol is calculated for each plant and this level is decomposed into its technical and allocative sources. Results show that, on average, plants in our sample may be able to reduce GHG emissions by a maximum of 6% or by 2.94 Gg per quarter. Input and output allocations that maximize returns over operating costs (ROOC) are also found based on observed prices. The environmentally efficient allocation, the ROOC-maximizing allocation, and the observed allocation for each plant are combined to calculate economic (shadow) cost of reducing greenhouse gas emissions. These shadow costs gauge the extent to which there is a trade off or a complementarity between environmental and economic targets. Results reveal that, at current activity levels, plants may have room for simultaneous improvement of environmental efficiency and economic profitability. -- Highlights: ► Environmental efficiency of ethanol plants in the North Central US is evaluated. ► Economic (shadow) cost of reducing greenhouse gas emissions is calculated. ► Feasible changes in the mix of inputs and byproducts can reduce GHG emissions. ► On average plants may be able to reduce GHG emissions by 2.94 Gg per quarter. ► GHG reductions may be achieved at a moderate or zero operating cost.

Fed-batch production of concentrated fructose syrup and ethanol using Saccharomyces cerevisiae ATCC 36859

Energy Technology Data Exchange (ETDEWEB)

Koren, D W [CANMET, Ottawa, ON (Canada); Duvnjak, Z [Univ. of Ottawa, ON (Canada). Dept. of Chemical Engineering

1992-01-01

A fed-batch process is used for the production of concentrated pure fructose syrup and ethanol from various glucose/fructose mixtures by S.cerevisiae ATCC 36859. Applying this technique, glucose-free fructose syrups with over 250 g/l of this sugar were obtained using High Fructose Corn Syrup and hydrolyzed Jerusalem artichoke juice. Bey encouraging ethanol evaporation from the reactor and condensing it, a separate ethanol product with a concentration of up to 350 g/l was also produced. The rates of glucose consumption and ethanol production were higher than in classical batch ethanol fermentation processes. (orig.).

Ethanol emission from loose corn silage and exposed silage particles

Science.gov (United States)

Hafner, Sasha D.; Montes, Felipe; Rotz, C. Alan; Mitloehner, Frank

2010-11-01

Silage on dairy farms has been identified as a major source of volatile organic compound (VOC) emissions. However, rates of VOC emission from silage are not accurately known. In this work, we measured ethanol (a dominant silage VOC) emission from loose corn silage and exposed corn silage particles using wind tunnel systems. Flux of ethanol was highest immediately after exposing loose silage samples to moving air (as high as 220 g m -2 h -1) and declined by as much as 76-fold over 12 h as ethanol was depleted from samples. Emission rate and cumulative 12 h emission increased with temperature, silage permeability, exposed surface area, and air velocity over silage samples. These responses suggest that VOC emission from silage on farms is sensitive to climate and management practices. Ethanol emission rates from loose silage were generally higher than previous estimates of total VOC emission rates from silage and mixed feed. For 15 cm deep loose samples, mean cumulative emission was as high as 170 g m -2 (80% of initial ethanol mass) after 12 h of exposure to an air velocity of 5 m s -1. Emission rates measured with an emission isolation flux chamber were lower than rates measured in a wind tunnel and in an open setting. Results show that the US EPA emission isolation flux chamber method is not appropriate for estimating VOC emission rates from silage in the field.

The impact of ethanol production on food prices: The role of interplay between the U.S. and Brazil

International Nuclear Information System (INIS)

Monteiro, Nathalia; Altman, Ira; Lahiri, Sajal

2012-01-01

Food prices have increased rapidly in recent years, and so has ethanol production. Some studies have claimed that there is a connection between the two. The main purpose of this paper is to add to this literature by examining the influence that the interplay between Brazil and the U.S. in ethanol production has on food prices. Specifically, and controlling for other variables, which have been shown to affect food prices, we investigate whether sugarcane ethanol and corn ethanol production have similar impacts on food prices, and whether ethanol productivity affects food prices. We find a positive significant effect of Brazilian market share in world ethanol market on relative food prices. We also find that an increase of Brazilian cane ethanol area has a negative effect on relative food prices. - Highlights: ► We examine if sugarcane ethanol and corn ethanol have similar impacts on food price. ► We examine if ethanol productivity affects food prices. ► We control for many other variables, which have been shown to affect food prices. ► Brazilian market share in ethanol market has a positive effect on food prices. ► Brazilian cane ethanol area has a negative effect on relative food prices.

Ethanol, Corn, and Soybean Price Relations in a Volatile Vehicle-Fuels Market

Directory of Open Access Journals (Sweden)

Cesar Escalante

2009-06-01

Full Text Available The rapid upward shift in ethanol demand has raised concerns about ethanol’s impact on the price level and volatility of agricultural commodities. The popular press attributes much of this volatility in commodity prices to a price bubble in ethanol fuel and recent deflation. Market economics predicts not only a softening of demand to high commodity prices but also a positive supply response. This volatility in ethanol and commodity prices are investigated using cointegration, vector error corrections (VECM, and multivariate generalized autoregressive conditional heteroskedascity (MGARCH models. In terms of derived demand theory, results support ethanol and oil demands as derived demands from vehicle-fuel production. Gasoline prices directly influence the prices of ethanol and oil. However, of greater significance for the fuel versus food security issue, results support the effect of agricultural commodity prices as market signals which restore commodity markets to their equilibriums after a demand or supply event (shock. Such shocks may in the short-run increase agricultural commodity prices, but decentralized freely operating markets will mitigate the persistence of these shocks. Results indicate in recent years there are no long-run relations among fuel (ethanol, oil and gasoline prices and agricultural commodity (corn and soybean prices.

A novel cell factory for efficient production of ethanol from dairy waste

DEFF Research Database (Denmark)

Liu, Jianming; Dantoft, Shruti Harnal; Würtz, Anders

2016-01-01

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...

Impact of Corn Residue Removal on Crop and Soil Productivity

Science.gov (United States)

Johnson, J. M.; Wilhelm, W. W.; Hatfield, J. L.; Voorhees, W. B.; Linden, D.

2003-12-01

Over-reliance on imported fuels, increasing atmospheric levels of greenhouses and sustaining food production for a growing population are three of the most important problems facing society in the mid-term. The US Department of Energy and private enterprise are developing technology necessary to use high cellulose feedstock, such as crop residues, for ethanol production. Based on production levels, corn (Zea mays L.) residue has potential as a biofuel feedstock. Crop residues are a renewable and domestic fuel source, which can reduce the rate of fossil fuel use (both imported and domestic) and provide an additional farm commodity. Crop residues protect the soil from wind and water erosion, provide inputs to form soil organic matter (a critical component determining soil quality) and play a role in nutrient cycling. Crop residues impact radiation balance and energy fluxes and reduce evaporation. Therefore, the benefits of using crop residues as fuel, which removes crop residues from the field, must be balanced against negative environmental impacts (e.g. soil erosion), maintaining soil organic matter levels, and preserving or enhancing productivity. All ramifications of new management practices and crop uses must be explored and evaluated fully before an industry is established. There are limited numbers of long-term studies with soil and crop responses to residue removal that range from negative to negligible. The range of crop and soil responses to crop residue removal was attributed to interactions with climate, management and soil type. Within limits, corn residue can be harvested for ethanol production to provide a renewable, domestic source of energy feedstock that reduces greenhouse gases. Removal rates must vary based on regional yield, climatic conditions and cultural practices. Agronomists are challenged to develop a protocol (tool) for recommending maximum permissible removal rates that ensure sustained soil productivity.

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

Energy Technology Data Exchange (ETDEWEB)

Chen, Xiaowen; Jennings, Ed; Shekiro, Joe; Kuhn, Erik M.; O' Brien, Marykate; Wang, Wei; Schell, Daniel J.; Himmel, Mike; Elander, Richard T.; Tucker, Melvin P.

2015-04-03

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 enzymatic 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.

Agricultural production and nutrient runoff in the Corn Belt ...

Science.gov (United States)

Agricultural production in the Corn Belt region of the Upper Mississippi River Basin (UMRB) remains a leading source of nitrogen runoff that contributes to the annual hypoxic 'Dead Zone' in the Gulf of Mexico. The rise of corn production, land conversion, and fertilizer use in response to ethanol policy incentives in recent years is well documented and may worsen this effect. We develop a spatially distributed dynamic environmental performance index (EPI), accounting for both desirable agricultural outputs and undesirable nonpoint source emissions from farm production, to examine the corresponding changes in environmental performance within the UMRB between 2002 and 2007, which is characterized by increasing policy incentives for ethanol production. County-level production data from the USDA agricultural census are aggregated to hydrologic unit code (HUC8) boundaries using a geographic information system (GIS), and a previously developed statistical model, which includes net anthropogenic nitrogen inputs (NANI) as well as precipitation and land use characteristics as inputs, is used to estimate annual nitrogen loadings delivered to streams from HUC8 watersheds. The EPI allows us to decompose performance of each HUC8 region over time into changes in productive efficiency and emissions efficiency. To our knowledge, this is the first study to examine the corresponding changes in environmental performance for producers in this region at the watershed scale. The resu

Agronomic impacts of production scale harvesting of corn stover for cellulosic ethanol production in Central Iowa

Science.gov (United States)

Schau, Dustin

This thesis investigates the impacts of corn stover harvest in Central Iowa with regards to nutrient removal, grain yield impacts and soil tilth. Focusing on phosphorus and potassium removal due to production of large, square bales of corn stover, 3.7 lb P2O5 and 18.7 lb K 2O per ton of corn stover were removed in 2011. P2O 5 removal remained statistically the same in 2012, but K2O decreased to 15.1 lb per ton of corn stover. Grain cart data showed no statistical difference in grain yield between harvest treatments, but yield monitor data showed a 3 - 17 bu/ac increase in 2012 and hand samples showed a 4 - 21 bu/ac increase in 2013. Corn stover residue levels decreased below 30% coverage when corn stover was harvested the previous fall and conventional tillage methods were used, but incorporating reduced tillage practices following corn stover harvest increased residue levels back up to 30% coverage. Corn emergence rates increased by at least 2,470 more plants per acre within the first three days of spiking, but final populations between harvest and nonharvest corn stover treatments were the same. Inorganic soil nitrogen in the form of ammonium and nitrate were not directly impacted by corn stover harvest, but it is hypothesized that weather patterns had a greater impact on nitrogen availability. Lastly, soil organic matter did not statistically change from 2011 to 2013 due to corn stover removal, even when analyzed within single soil types.

Rheology of corn stover slurries during fermentation to ethanol

Science.gov (United States)

Ghosh, Sanchari; Epps, Brenden; Lynd, Lee

2017-11-01

In typical processes that convert cellulosic biomass into ethanol fuel, solubilization of the biomass is carried out by saccharolytic enzymes; however, these enzymes require an expensive pretreatment step to make the biomass accessible for solubilization (and subsequent fermentation). We have proposed a potentially-less-expensive approach using the bacterium Clostridium thermocellum, which can initiate fermentation without pretreatment. Moreover, we have proposed a ``cotreatment'' process, in which fermentation and mechanical milling occur alternately so as to achieve the highest ethanol yield for the least milling energy input. In order to inform the energetic requirements of cotreatment, we experimentally characterized the rheological properties of corn stover slurries at various stages of fermentation. Results show that a corn stover slurry is a yield stress fluid, with shear thinning behavior well described by a power law model. Viscosity decreases dramatically upon fermentation, controlling for variables such as solids concentration and particle size distribution. To the authors' knowledge, this is the first study to characterize the changes in the physical properties of biomass during fermentation by a thermophilic bacterium.

Improving the corn-ethanol industry: studying protein separation techniques to obtain higher value added product options for distillers grains

NARCIS (Netherlands)

Brehmer, B.; Bals, B.; Sanders, J.P.M.; Dale, B.

2008-01-01

Currently in America the biofuel ethanol is primarily being produced by the dry grind technique to obtain the starch contained in the corn grains and subsequently subjected to fermentation. This so-called 1st generation technology has two setbacks; first the lingering debate whether its life cycle

Strategic design and investment capacity planning of the ethanol supply chain under price uncertainty

International Nuclear Information System (INIS)

Dal-Mas, Matteo; Giarola, Sara; Zamboni, Andrea; Bezzo, Fabrizio

2011-01-01

Fossil fuel depletion and the increase of greenhouse gases emissions has been pushing the search for alternative fuels for automotive transport. The European Union has identified biofuel technology as one option for reducing its dependence on imported energy. Ethanol is a promising biofuel, but great uncertainty on the business profitability has recently determined a slowdown in the industry expansion. In particular, geographical plant location, biomass price fluctuation and fuel demand variability severely constrain the economic viability of new ethanol facilities. In this work a dynamic, spatially explicit and multi-echelon Mixed Integer Linear Program (MILP) modeling framework is presented to help decision-makers and potential investors assessing economic performances and risk on investment of the entire biomass-based ethanol supply chain. A case study concerning the corn-to-ethanol production supply chain in Northern Italy is used to demonstrate the effectiveness of the proposed modeling approach. The mathematical pattern addresses the issue of optimizing the ethanol supply network over a ten years' time period under uncertainty on biomass production cost and product selling price. The model allows optimizing economic performances and minimize financial risk on investment by identifying the best network topology in terms of biomass cultivation site locations, ethanol production plant capacities, location and transport logistics. -- Highlights: →A dynamic spatially explicit Mixed Integer Linear Program (MILP) of the entire corn-based ethanol supply chain is proposed. →Uncertainty on corn price and ethanol selling price is taken into account. →The model allows assessing and optimizing the supply chain economic performance and risk on investment. →A case study concerning the corn-to-ethanol production in Northern Italy demonstrates the effectiveness of the approach.

Impacts of retrofitting analysis on first generation ethanol production: process design and techno-economics.

Science.gov (United States)

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.

Corn

OpenAIRE

Sherwood, Brianne; Hawks, Amanda

2011-01-01

We have so much corn right now it's coming out of our ears (great pun, right?). And it's SO incredibly cheap! This is probably because the US produces 42% of the world's corn! Most of it is used for animal feed, but other uses include exporting to other countries, human food, seed, and industrial uses such as ethanol production. Because there is so much corn available here in the U.S. You can find it in a lot more foods than you think. It's in peanut butter, snack foods, soft drinks, multivit...

Production of ethanol from winter barley by the EDGE (enhanced dry grind enzymatic process

Directory of Open Access Journals (Sweden)

Kurantz M

2010-04-01

Full Text Available Abstract Background US legislation requires the use of advanced biofuels to be made from non-food feedstocks. However, commercialization of lignocellulosic ethanol technology is more complex than expected and is therefore running behind schedule. This is creating a demand for non-food, but more easily converted, starch-based feedstocks other than corn that can fill the gap until the second generation technologies are commercially viable. Winter barley is such a feedstock but its mash has very high viscosity due to its high content of β-glucans. This fact, along with a lower starch content than corn, makes ethanol production at the commercial scale a real challenge. Results A new fermentation process for ethanol production from Thoroughbred, a winter barley variety with a high starch content, was developed. The new process was designated the EDGE (enhanced dry grind enzymatic process. In this process, in addition to the normal starch-converting enzymes, two accessory enzymes were used to solve the β-glucan problem. First, β-glucanases were used to hydrolyze the β-glucans to oligomeric fractions, thus significantly reducing the viscosity to allow good mixing for the distribution of the yeast and nutrients. Next, β-glucosidase was used to complete the β-glucan hydrolysis and to generate glucose, which was subsequently fermented in order to produce additional ethanol. While β-glucanases have been previously used to improve barley ethanol production by lowering viscosity, this is the first full report on the benefits of adding β-glucosidases to increase the ethanol yield. Conclusions In the EDGE process, 30% of total dry solids could be used to produce 15% v/v ethanol. Under optimum conditions an ethanol yield of 402 L/MT (dry basis or 2.17 gallons/53 lb bushel of barley with 15% moisture was achieved. The distillers dried grains with solubles (DDGS co-product had extremely low β-glucan (below 0.2% making it suitable for use in both ruminant

Accounting for all sugars produced during integrated production of ethanol from lignocellulosic biomass.

Science.gov (United States)

Schell, Daniel J; Dowe, Nancy; Chapeaux, Alexandre; Nelson, Robert S; Jennings, Edward W

2016-04-01

Accurate mass balance and conversion data from integrated operation is needed to fully elucidate the economics of biofuel production processes. This study explored integrated conversion of corn stover to ethanol and highlights techniques for accurate yield calculations. Acid pretreated corn stover (PCS) produced in a pilot-scale reactor was enzymatically hydrolyzed and the resulting sugars were fermented to ethanol by the glucose-xylose fermenting bacteria, Zymomonas mobilis 8b. The calculations presented here account for high solids operation and oligomeric sugars produced during pretreatment, enzymatic hydrolysis, and fermentation, which, if not accounted for, leads to overestimating ethanol yields. The calculations are illustrated for enzymatic hydrolysis and fermentation of PCS at 17.5% and 20.0% total solids achieving 80.1% and 77.9% conversion of cellulose and xylan to ethanol and ethanol titers of 63g/L and 69g/L, respectively. These procedures will be employed in the future and the resulting information used for techno-economic analysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Progress in the production of bioethanol on starch-based feedstocks

Directory of Open Access Journals (Sweden)

Dragiša Savić

2009-10-01

Full Text Available Bioethanol produced from renewable biomass, such as sugar, starch, or lignocellulosic materials, is one of the alternative energy resources, which is both renewable and environmentally friendly. Although, the priority in global future ethanol production is put on lignocellulosic processing, which is considered as one of the most promising second-generation biofuel technologies, the utilizetion of lignocellulosic material for fuel ethanol is still under improvement. Sugar- based (molasses, sugar cane, sugar beet and starch-based (corn, wheat, triticale, potato, rice, etc. feedstock are still currently predominant at the industrial level and they are, so far, economically favorable compared to lingocelluloses. Currently, approx. 80 % of total world ethanol production is obtained from the fermentation of simple sugars by yeast. In Serbia, one of the most suitable and available agricultural raw material for the industrial ethanol production are cereals such as corn, wheat and triticale. In addition, surpluses of this feedstock are being produced in our country constantly. In this paper, a brief review of the state of the art in bioethanol production and biomass availability is given, pointing out the progress possibilities on starch-based production. The progress possibilities are discussed in the domain of feedstock choice and pretreatment, optimization of fermentation, process integration and utilization of the process byproducts.

Characteristics of Corn Stover Pretreated with Liquid Hot Water and Fed-Batch Semi-Simultaneous Saccharification and Fermentation for Bioethanol Production

Science.gov (United States)

Li, Xuezhi; Lu, Jie; Zhao, Jian; Qu, Yinbo

2014-01-01

Corn stover is a promising feedstock for bioethanol production because of its abundant availability in China. To obtain higher ethanol concentration and higher ethanol yield, liquid hot water (LHW) pretreatment and fed-batch semi-simultaneous saccharification and fermentation (S-SSF) were used to enhance the enzymatic digestibility of corn stover and improve bioconversion of cellulose to ethanol. The results show that solid residues from LHW pretreatment of corn stover can be effectively converted into ethanol at severity factors ranging from 3.95 to 4.54, and the highest amount of xylan removed was approximately 89%. The ethanol concentrations of 38.4 g/L and 39.4 g/L as well as ethanol yields of 78.6% and 79.7% at severity factors of 3.95 and 4.54, respectively, were obtained by fed-batch S-SSF in an optimum conditions (initial substrate consistency of 10%, and 6.1% solid residues added into system at the prehydrolysis time of 6 h). The changes in surface morphological structure, specific surface area, pore volume and diameter of corn stover subjected to LHW process were also analyzed for interpreting the possible improvement mechanism. PMID:24763192

High titer L-lactic acid production from corn stover with minimum wastewater generation and techno-economic evaluation based on Aspen plus modeling.

Science.gov (United States)

Liu, Gang; Sun, Jiaoe; Zhang, Jian; Tu, Yi; Bao, Jie

2015-12-01

Technological potentials of l-lactic acid production from corn stover feedstock were investigated by experimental and techno-economic studies. An optimal performance with 104.5 g/L in l-lactic acid titer and 71.5% in overall yield from cellulose in corn stover to l-lactic acid using an engineered Pediococcus acidilactici strain were obtained by overcoming several technical barriers. A rigorous Aspen plus model for l-lactic acid production starting from dry dilute acid pretreated and biodetoxified corn stover was developed. The techno-economic analysis shows that the minimum l-lactic acid selling price (MLSP) was $0.523 per kg, which was close to that of the commercial l-lactic acid produced from starch feedstock, and 24% less expensive than that of ethanol from corn stover, even though the xylose utilization was not considered. The study provided a prototype of industrial application and an evaluation model for high titer l-lactic acid production from lignocellulose feedstock. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fumonisins B1 and B2 in the corn-milling process and corn-based products, and evaluation of estimated daily intake.

Science.gov (United States)

Savi, Geovana D; Piacentini, Karim C; Marchi, Djeini; Scussel, Vildes M

2016-01-01

The distribution of fumonisins (FBs: FB1 and FB2) in the corn-milling process and in corn-based products, as well as daily intake estimates for the Brazilian population were evaluated. Among corn fractions samples, corn meal had the highest mean concentration of FB1 (1305 µg kg(-1)) and FB2 (651 µg kg(-1)) and a distribution factors of 452% and 256% in relation to corn grain, respectively. On the other hand, the distribution factor of FB1 and FB2 in corn flour was found to be 144% and 88% respectively, which demonstrates that fumonisins in this fraction were reduced compared with corn grain. As a result, almost half the corn meal samples (47%) would be non-compliant with future Brazilian regulation (2017) for fumonisins. However, corn-based products, such as corn flakes and popcorn, were in compliance with the regulation. The average probable daily intake and maximum probable daily intake of fumonisins estimated for the Santa Catarina state (Brazil) population were below the provisional maximum tolerable daily intake of 2 µg kg(-1) body weight day(-1) for all corn samples. Despite this, the adoption of practices to control the occurrence of fumonisins should be applied to the corn-milling fractions that may contain a higher concentration of this toxin, such as corn meal, often used for animal feed in Brazil.

Industrial symbiosis: corn ethanol fermentation, hydrothermal carbonization, and anaerobic digestion.

Science.gov (United States)

Wood, Brandon M; Jader, Lindsey R; Schendel, Frederick J; Hahn, Nicholas J; Valentas, Kenneth J; McNamara, Patrick J; Novak, Paige M; Heilmann, Steven M

2013-10-01

The production of dry-grind corn ethanol results in the generation of intermediate products, thin and whole stillage, which require energy-intensive downstream processing for conversion into commercial animal feed products. Hydrothermal carbonization of thin and whole stillage coupled with anaerobic digestion was investigated as alternative processing methods that could benefit the industry. By substantially eliminating evaporation of water, reductions in downstream energy consumption from 65% to 73% were achieved while generating hydrochar, fatty acids, treated process water, and biogas co-products providing new opportunities for the industry. Processing whole stillage in this manner produced the four co-products, eliminated centrifugation and evaporation, and substantially reduced drying. With thin stillage, all four co-products were again produced, as well as a high quality animal feed. Anaerobic digestion of the aqueous product stream from the hydrothermal carbonization of thin stillage reduced chemical oxygen demand (COD) by more than 90% and converted 83% of the initial COD to methane. Internal use of this biogas could entirely fuel the HTC process and reduce overall natural gas usage. Copyright © 2013 Wiley Periodicals, Inc.

The Role of Cellulosic Ethanol in Transportation

Energy Technology Data Exchange (ETDEWEB)

Robert M. Neilson, Jr.

2007-10-01

Petroleum provides essentially all of the energy used today in the transportation sector. To reduce this dependence on fossil energy, other fuels are beginning to be used, notably ethanol and biodiesel. Almost all fuel ethanol is produced by the conversion of corn grain to starch with subsequent fermentation to ethanol. In 2006, almost 5 billion gallons of fuel ethanol were produced, which used 17% of domestic corn production. The DOE has a goal to displace 30% of motor gasoline demand or 60 billion gallons per year by 2030. To achieve this goal, production of ethanol from lignocellulosic sources (e.g., agricultural residues, forest residues, and dedicated energy crops) is needed. This paper will describe the production of cellulosic ethanol as well as the issues and benefits associated with its production.

Characterization of very high gravity ethanol fermentation of corn mash. Effect of glucoamylase dosage, pre-saccharification and yeast strain

Energy Technology Data Exchange (ETDEWEB)

Devantier, R. [Starch, Applied Discovery, Research and Development, Novozymes A/S, Bagsvaerd (Denmark); Center for Microbial Biotechnology, BioCentrum-DTU, Technical Univ. of Denmark, Kgs Lyngby (Denmark); Pedersen, S. [Starch, Applied Discovery, Research and Development, Novozymes A/S, Bagsvaerd (Denmark); Olsson, L. [Center for Microbial Biotechnology, BioCentrum-DTU, Technical Univ. of Denmark, Kgs Lyngby (Denmark)

2005-09-01

Ethanol was produced from very high gravity mashes of dry milled corn (35% w/w total dry matter) under simultaneous saccharification and fermentation conditions. The effects of glucoamylase dosage, pre-saccharification and Saccharomyces cerevisiae strain on the growth characteristics such as the ethanol yield and volumetric and specific productivity were determined. It was shown that higher glucoamylase doses and/or pre-saccharification accelerated the simultaneous saccharification and fermentation process and increased the final ethanol concentration from 106 to 126 g/kg although the maximal specific growth rate was decreased. Ethanol production was not only growth related, as more than half of the total saccharides were consumed and more than half of the ethanol was produced during the stationary phase. Furthermore, a high stress tolerance of the applied yeast strain was found to be crucial for the outcome of the fermentation process, both with regard to residual saccharides and final ethanol concentration. The increased formation of cell mass when a well-suited strain was applied increased the final ethanol concentration, since a more complete fermentation was achieved. (orig.)

Effects of Fuel Ethanol Use on Fuel-Cycle Energy and Greenhouse Gas Emissions

International Nuclear Information System (INIS)

C. Saricks; D. Santini; M. Wang

1999-01-01

We estimated the effects on per-vehicle-mile fuel-cycle petroleum use, greenhouse gas (GHG) emissions, and energy use of using ethanol blended with gasoline in a mid-size passenger car, compared with the effects of using gasoline in the same car. Our analysis includes petroleum use, energy use, and emissions associated with chemicals manufacturing, farming of corn and biomass, ethanol production, and ethanol combustion for ethanol; and petroleum use, energy use, and emissions associated with petroleum recovery, petroleum refining, and gasoline combustion for gasoline. For corn-based ethanol, the key factors in determining energy and emissions impacts include energy and chemical usage intensity of corn farming, energy intensity of the ethanol plant, and the method used to estimate energy and emissions credits for co-products of corn ethanol. The key factors in determining the impacts of cellulosic ethanol are energy and chemical usage intensity of biomass farming, ethanol yield per dry ton of biomass, and electricity credits in cellulosic ethanol plants. The results of our fuel-cycle analysis for fuel ethanol are listed below. Note that, in the first half of this summary, the reductions cited are per-vehicle-mile traveled using the specified ethanol/gasoline blend instead of conventional (not reformulated) gasoline. The second half of the summary presents estimated changes per gallon of ethanol used in ethanol blends. GHG emissions are global warming potential (GWP)-weighted, carbon dioxide (CO2)-equivalent emissions of CO2, methane (CH4), and nitrous oxide (N2O)

A lignocellulosic ethanol strategy via nonenzymatic sugar production: process synthesis and analysis.

Science.gov (United States)

Han, Jeehoon; Luterbacher, Jeremy S; Alonso, David Martin; Dumesic, James A; Maravelias, Christos T

2015-04-01

The work develops a strategy for the production of ethanol from lignocellulosic biomass. In this strategy, the cellulose and hemicellulose fractions are simultaneously converted to sugars using a γ-valerolactone (GVL) solvent containing a dilute acid catalyst. To effectively recover GVL for reuse as solvent and biomass-derived lignin for heat and power generation, separation subsystems, including a novel CO2-based extraction for the separation of sugars from GVL, lignin and humins have been designed. The sugars are co-fermented by yeast to produce ethanol. Furthermore, heat integration to reduce utility requirements is performed. It is shown that this strategy leads to high ethanol yields and the total energy requirements could be satisfied by burning the lignin. The integrated strategy using corn stover feedstock leads to a minimum selling price of $5 per gallon of gasoline equivalent, which suggests that it is a promising alternative to current biofuels production approaches. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ethanol Transportation Backgrounder

OpenAIRE

Denicoff, Marina R.

2007-01-01

For the first 6 months of 2007, U.S. ethanol production totaled nearly 3 billion gallons—32 percent higher than the same period last year. As of August 29, there were 128 ethanol plants with annual production capacity totaling 6.78 billion gallons, and an additional 85 plants were under construction. U.S. ethanol production capacity is expanding rapidly and is currently expected to exceed 13 billion gallons per year by early 2009, if not sooner. Ethanol demand has increased corn prices and le...

Ethanol Production from Various Sugars and Cellulosic Biomass by White Rot Fungus Lenzites betulinus.

Science.gov (United States)

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.

Life cycle greenhouse gas (GHG) impacts of a novel process for converting food waste to ethanol and co-products

International Nuclear Information System (INIS)

Ebner, Jacqueline; Babbitt, Callie; Winer, Martin; Hilton, Brian; Williamson, Anahita

2014-01-01

Highlights: • Co-fermentation using SSF at ambient temperature has potential as an ethanol pathway. • Bio-refinery GHG emissions are similar to corn and MSW ethanol production processes. • Net production GHG impact is negative with inclusion of waste disposal avoidance. • Food waste diversion from landfills is the largest contributor to GHG benefits. - Abstract: Waste-to-ethanol conversion is a promising technology to provide renewable transportation fuel while mitigating feedstock risks and land use conflicts. It also has the potential to reduce environmental impacts from waste management such as greenhouse gas (GHG) emissions that contribute to climate change. This paper analyzes the life cycle GHG emissions associated with a novel process for the conversion of food processing waste into ethanol (EtOH) and the co-products of compost and animal feed. Data are based on a pilot plant co-fermenting retail food waste with a sugary industrial wastewater, using a simultaneous saccharification and fermentation (SSF) process at room temperature with a grinding pretreatment. The process produced 295 L EtOH/dry t feedstock. Lifecycle GHG emissions associated with the ethanol production process were 1458 gCO 2 e/L EtOH. When the impact of avoided landfill emissions from diverting food waste to use as feedstock are considered, the process results in net negative GHG emissions and approximately 500% improvement relative to corn ethanol or gasoline production. This finding illustrates how feedstock and alternative waste disposal options have important implications in life cycle GHG results for waste-to-energy pathways

Zymomonas mobilis for fuel ethanol and higher value products.

Science.gov (United States)

Rogers, P L; Jeon, Y J; Lee, K J; Lawford, H G

2007-01-01

High oil prices, increasing focus on renewable carbohydrate-based feedstocks for fuels and chemicals, and the recent publication of its genome sequence, have provided continuing stimulus for studies on Zymomonas mobilis. However, despite its apparent advantages of higher yields and faster specific rates when compared to yeasts, no commercial scale fermentations currently exist which use Z. mobilis for the manufacture of fuel ethanol. This may change with the recent announcement of a Dupont/Broin partnership to develop a process for conversion of lignocellulosic residues, such as corn stover, to fuel ethanol using recombinant strains of Z. mobilis. The research leading to the construction of these strains, and their fermentation characteristics, are described in the present review. The review also addresses opportunities offered by Z. mobilis for higher value products through its metabolic engineering and use of specific high activity enzymes.

Evaluation of the Potential for the Production of Lignocellulosic Based Ethanol at Existing Corn Ethanol Facilities: Final Subcontract Report, 2 March 2000 - 30 March 2002

Energy Technology Data Exchange (ETDEWEB)

2002-07-01

Subcontract report on opportunities to explore the business potential provided by converting biomass to products such as ethanol. The goals of this study were: (1) To provide the opportunity to explore the business potential provided by converting biomass to products such as ethanol. (2) To take advantage of the grain-processing infrastructure by investigating the co-location of additional biomass conversion facilities at an existing plant site.

A bacterial cell factory for efficient production of ethanol from whey

DEFF Research Database (Denmark)

2017-01-01

The invention relates to a method for homo-ethanol production from lactose using a genetically modified lactic acid bacterium of the invention, where the cells are provided with a substrate comprising dairy waste supplemented with an amino nitrogen source (such as acid hydrolysed corn steep liquo...

Effects of Fuel Ethanol Use on Fuel-Cycle Energy and Greenhouse Gas Emissions; TOPICAL

International Nuclear Information System (INIS)

C. Saricks; D. Santini; M. Wang

1999-01-01

We estimated the effects on per-vehicle-mile fuel-cycle petroleum use, greenhouse gas (GHG) emissions, and energy use of using ethanol blended with gasoline in a mid-size passenger car, compared with the effects of using gasoline in the same car. Our analysis includes petroleum use, energy use, and emissions associated with chemicals manufacturing, farming of corn and biomass, ethanol production, and ethanol combustion for ethanol; and petroleum use, energy use, and emissions associated with petroleum recovery, petroleum refining, and gasoline combustion for gasoline. For corn-based ethanol, the key factors in determining energy and emissions impacts include energy and chemical usage intensity of corn farming, energy intensity of the ethanol plant, and the method used to estimate energy and emissions credits for co-products of corn ethanol. The key factors in determining the impacts of cellulosic ethanol are energy and chemical usage intensity of biomass farming, ethanol yield per dry ton of biomass, and electricity credits in cellulosic ethanol plants. The results of our fuel-cycle analysis for fuel ethanol are listed below. Note that, in the first half of this summary, the reductions cited are per-vehicle-mile traveled using the specified ethanol/gasoline blend instead of conventional (not reformulated) gasoline. The second half of the summary presents estimated changes per gallon of ethanol used in ethanol blends. GHG emissions are global warming potential (GWP)-weighted, carbon dioxide (CO2)-equivalent emissions of CO2, methane (CH4), and nitrous oxide (N2O)

Ethanol production in Brazil: a bridge between science and industry

Directory of Open Access Journals (Sweden)

Mario Lucio Lopes

Full Text Available ABSTRACT In the last 40 years, several scientific and technological advances in microbiology of the fermentation have greatly contributed to evolution of the ethanol industry in Brazil. These contributions have increased our view and comprehension about fermentations in the first and, more recently, second-generation ethanol. Nowadays, new technologies are available to produce ethanol from sugarcane, corn and other feedstocks, reducing the off-season period. Better control of fermentation conditions can reduce the stress conditions for yeast cells and contamination by bacteria and wild yeasts. There are great research opportunities in production processes of the first-generation ethanol regarding high-value added products, cost reduction and selection of new industrial yeast strains that are more robust and customized for each distillery. New technologies have also focused on the reduction of vinasse volumes by increasing the ethanol concentrations in wine during fermentation. Moreover, conversion of sugarcane biomass into fermentable sugars for second-generation ethanol production is a promising alternative to meet future demands of biofuel production in the country. However, building a bridge between science and industry requires investments in research, development and transfer of new technologies to the industry as well as specialized personnel to deal with new technological challenges.

Energy analysis of ethanol production from sweet sorghum

Energy Technology Data Exchange (ETDEWEB)

Worley, J.W. (Georgia Univ., Athens, GA (United States). Dept. of Agricultural Engineering); Vaughan, D.H.; Cundiff, J.S. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Agricultural Engineering)

1992-01-01

The Piedmont System is a collection of equipment for efficiently removing the juice from sweet sorghum stalks for the production of ethanol. The concept is to separate the whole stalks into pith and rind-leaf fractions, pass only the pith fraction through a screw press, and thus achieve an improvement in juice-expression efficiency and press capacity. An energy analysis was done for two options of this proposed harvesting/processing system: (Option 1) The juice is evaporated to syrup and used throughout the year to produce ethanol, and the by-products are used as cattle feed. (Option 2) The juice is fermented as it is harvested, and the by-products (along with other cellulosic materials) are used as feedstock for the remainder of the year. Energy ratios (energy output/energy input) of 0.9, 1.1 and 0.8 were found for sweet sorghum Option 1, sweet sorghum Option 2, and corn, respectively, as feedstocks for ethanol. If only liquid fuels are considered, the ratios are increased to 3.5, 7.9 and 4.5. (author).

High Speed/ Low Effluent Process for Ethanol

Energy Technology Data Exchange (ETDEWEB)

M. Clark Dale

2006-10-30

n this project, BPI demonstrated a new ethanol fermentation technology, termed the High Speed/ Low Effluent (HS/LE) process on both lab and large pilot scale as it would apply to wet mill and/or dry mill corn ethanol production. The HS/LE process allows very rapid fermentations, with 18 to 22% sugar syrups converted to 9 to 11% ethanol ‘beers’ in 6 to 12 hours using either a ‘consecutive batch’ or ‘continuous cascade’ implementation. This represents a 5 to 8X increase in fermentation speeds over conventional 72 hour batch fermentations which are the norm in the fuel ethanol industry today. The ‘consecutive batch’ technology was demonstrated on a large pilot scale (4,800 L) in a dry mill corn ethanol plant near Cedar Rapids, IA (Xethanol Biofuels). The pilot demonstrated that 12 hour fermentations can be accomplished on an industrial scale in a non-sterile industrial environment. Other objectives met in this project included development of a Low Energy (LE) Distillation process which reduces the energy requirements for distillation from about 14,000 BTU/gal steam ($0.126/gal with natural gas @ $9.00 MCF) to as low as 0.40 KW/gal electrical requirements ($0.022/gal with electricity @ $0.055/KWH). BPI also worked on the development of processes that would allow application of the HS/LE fermentation process to dry mill ethanol plants. A High-Value Corn ethanol plant concept was developed to produce 1) corn germ/oil, 2) corn bran, 3) ethanol, 4) zein protein, and 5) nutritional protein, giving multiple higher value products from the incoming corn stream.

Lignocellulosic Biomass to Ethanol Process Design and Economics Utilizing Co-Current Dilute Acid Prehydrolysis and Enzymatic Hydrolysis for Corn Stover

Energy Technology Data Exchange (ETDEWEB)

Aden, A.; Ruth, M.; Ibsen, K.; Jechura, J.; Neeves, K.; Sheehan, J.; Wallace, B.; Montague, L.; Slayton, A.; Lukas, J.

2002-06-01

and costing for the lignin combustor and boiler turbogenerator was reviewed by Reaction Engineering Inc. (REI) and Merrick & Company reviewed the wastewater treatment. Since then, NREL has engaged Harris Group (Harris) to perform vendor testing, process design, and costing of critical equipment identified during earlier work. This included solid/liquid separation and pretreatment reactor design and costing. Corn stover handling was also investigated to support DOE's decision to focus on corn stover as a feedstock for lignocellulosic ethanol. Working with Harris, process design and costing for these areas were improved through vendor designs, costing, and vendor testing in some cases. In addition to this work, enzyme costs were adjusted to reflect collaborative work between NREL and enzyme manufacturers (Genencor International and Novozymes Biotech) to provide a delivered enzyme for lignocellulosic feedstocks. This report is the culmination of our work and represents an updated process design and cost basis for the process using a corn stover feedstock. The process design and economic model are useful for predicting the cost benefits of proposed research. Proposed research results can be translated into modifications of the process design, and the economic impact can be assessed. This allows DOE, NREL, and other researchers to set priorities on future research with an understanding of potential reductions to the ethanol production cost. To be economically viable, ethanol production costs must be below market values for ethanol. DOE has chosen a target ethanol selling price of $1.07 per gallon as a goal for 2010. The conceptual design and costs presented here are based on a 2010 plant start-up date. The key research targets required to achieve this design and the $1.07 value are discussed in the report.

Development of synthetic chromosomes and improved microbial strains to utilize cellulosic feedstocks and express valuable coproducts for sustainable production of biofuels from corn

Science.gov (United States)

A sustainable biorefinery must convert a broad range of renewable feedstocks into a variety of product streams, including fuels, power, and value-added bioproducts. To accomplish this, microbial-based technologies that enable new commercially viable coproducts from corn-to-ethanol biofuel fermentati...

Comparison of corn and switchgrass on marginal soils for bioenergy

Energy Technology Data Exchange (ETDEWEB)

Varvel, G.E.; Vogel, K.P.; Mitchell, R.B. [USDA-ARS, 344 Keim Hall, University of Nebraska-Lincoln, P.O. Box 830937, Lincoln, NE 68583-0937 (United States); Follett, R.F. [USDA-ARS, Room S-100, 2150 Centre Avenue Building D, Ft. Collins, CO 80526-8119 (United States); Kimble, J.M. [USDA-NRCS, National Soil Survey Center, 100 Centennial Mall North, Lincoln, NE 68508-3866 (United States)

2008-01-15

Crop residues such as corn (Zea mays L.) stover are viewed as an abundant and inexpensive source of biomass that can be removed from fields to produce bioenergy. Assumptions include that with minimum or no-tillage farming methods, there will be no deleterious production or environmental effects. A long-term field study was established in eastern Nebraska, USA, to compare the switchgrass managed as a biomass energy crop versus no-till corn on a non-irrigated site, marginal for row-crop production, in the western Corn Belt. Our objective in this paper is to report on corn stover removal effects on corn grain yields and potential ethanol production in both cropping systems. Corn, under no-till management, and switchgrass were grown at three N fertilizer levels. In the first 5 years (2001-2005), removal of half the available stover significantly reduced corn yields. During that same time period, the potential ethanol yield for switchgrass was equal to or greater than the potential total ethanol yield of corn grain and harvested stover fertilized at the same optimum N rate. The effect of crop residue removal on crop productivity needs to be investigated in other agro-ecosystems and the potential use of dedicated perennial biomass energy crops should remain a viable renewable energy option on non-irrigated marginal croplands. (author)

Optimizing Blendstock Composition and Ethanol Feedstock to Reduce Gasoline Well-to-Pump CO 2 Emission

KAUST Repository

Zhang, Bo; Sarathy, Mani; Abdul-Manan, Amir F.N.

2017-01-01

Lifecycle CO2 emission of ethanol blended gasoline was simulated to investigate how fuel properties and composition affect overall emission. Fuel research octane number (RON), octane sensitivity and ethanol content (derived from sugarcane and corn) were varied in the simulations to formulate blended fuels that economically achieve target specifications. The well-to-pump (WTP) simulation results were then analyzed to understand the effects of fuel composition on emission. Elevated ethanol content displaces aromatics and olefins required in gasoline blendstock to reach a target fuel specification. The addition of greater sugarcane-based ethanol percentage in constant aromatics and olefins fuel reduces its WTP CO2 emission. Corn-based ethanol blending does not offer CO2 emission offset due to its high production emissions. The mixing of sugarcane-based with corn-based ethanol is shown to be a potentially effective method for achieving a blended fuel with a lower lifecycle CO2 emission. Besides CO2 emission, the total greenhouse gas (GHG) emission from land-use conversions (LUC), CH4, and N2O are also significant in determining the optimal fuel blend. Herein, we present preliminary results showing that total GHG emissions significantly increase when either corn or sugarcane ethanol is blended at even small percentages; detailed results will be addressed in future communications.

Optimizing Blendstock Composition and Ethanol Feedstock to Reduce Gasoline Well-to-Pump CO 2 Emission

KAUST Repository

Zhang, Bo

2017-06-02

Lifecycle CO2 emission of ethanol blended gasoline was simulated to investigate how fuel properties and composition affect overall emission. Fuel research octane number (RON), octane sensitivity and ethanol content (derived from sugarcane and corn) were varied in the simulations to formulate blended fuels that economically achieve target specifications. The well-to-pump (WTP) simulation results were then analyzed to understand the effects of fuel composition on emission. Elevated ethanol content displaces aromatics and olefins required in gasoline blendstock to reach a target fuel specification. The addition of greater sugarcane-based ethanol percentage in constant aromatics and olefins fuel reduces its WTP CO2 emission. Corn-based ethanol blending does not offer CO2 emission offset due to its high production emissions. The mixing of sugarcane-based with corn-based ethanol is shown to be a potentially effective method for achieving a blended fuel with a lower lifecycle CO2 emission. Besides CO2 emission, the total greenhouse gas (GHG) emission from land-use conversions (LUC), CH4, and N2O are also significant in determining the optimal fuel blend. Herein, we present preliminary results showing that total GHG emissions significantly increase when either corn or sugarcane ethanol is blended at even small percentages; detailed results will be addressed in future communications.

Economic, energy and environmental evaluations of biomass-based fuel ethanol projects based on life cycle assessment and simulation

International Nuclear Information System (INIS)

Yu Suiran; Tao Jing

2009-01-01

This paper summarizes the research of Monte Carlo simulation-based Economic, Energy and Environmental (3E) Life Cycle Assessment (LCA) of the three Biomass-based Fuel Ethanol (BFE) projects in China. Our research includes both theoretical study and case study. In the theoretical study part, 3E LCA models are structured, 3E Index Functions are defined and the Monte Carlo simulation is introduced to address uncertainties in BFE life cycle analysis. In the case study part, projects of Wheat-based Fuel Ethanol (WFE) in Central China, Corn-based Fuel Ethanol (CFE) in Northeast China, and Cassava-based Fuel Ethanol (CFE) in Southwest China are evaluated from the aspects of economic viability and investment risks, energy efficiency and airborne emissions. The life cycle economy assessment shows that KFE project in Guangxi is viable, while CFE and WFE projects are not without government's subsidies. Energy efficiency assessment results show that WFE, CFE and KFE projects all have positive Net Energy Values. Emissions results show that the corn-based E10 (a blend of 10% gasoline and 90% ethanol by volume), wheat-based E10 and cassava-base E10 have less CO 2 and VOC life cycle emissions than conventional gasoline, but wheat-based E10 and cassava-based E10 can generate more emissions of CO, CH 4 , N 2 O, NO x , SO 2 , PM 10 and corn-based E10 can has more emissions of CH 4 , N 2 O, NO x , SO, PM 10 .

Understanding the reductions in US corn ethanol production costs: an experience curve approach

NARCIS (Netherlands)

Hettinga, W.; Junginger, H.M.; Dekker, S.C.; Hoogwijk, M.; McAloon, A.; Hicks, K.

2009-01-01

The US is currently the world's largest ethanol producer. An increasing percentage is used as transportation fuel, but debates continue on its costs competitiveness and energy balance. In this study, technological development of ethanol production and resulting cost reductions are investigated by

Life-cycle assessment of corn-based butanol as a potential transportation fuel.

Energy Technology Data Exchange (ETDEWEB)

Wu, M.; Wang, M.; Liu, J.; Huo, H.; Energy Systems

2007-12-31

Butanol produced from bio-sources (such as corn) could have attractive properties as a transportation fuel. Production of butanol through a fermentation process called acetone-butanol-ethanol (ABE) has been the focus of increasing research and development efforts. Advances in ABE process development in recent years have led to drastic increases in ABE productivity and yields, making butanol production worthy of evaluation for use in motor vehicles. Consequently, chemical/fuel industries have announced their intention to produce butanol from bio-based materials. The purpose of this study is to estimate the potential life-cycle energy and emission effects associated with using bio-butanol as a transportation fuel. The study employs a well-to-wheels analysis tool--the Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET) model developed at Argonne National Laboratory--and the Aspen Plus{reg_sign} model developed by AspenTech. The study describes the butanol production from corn, including grain processing, fermentation, gas stripping, distillation, and adsorption for products separation. The Aspen{reg_sign} results that we obtained for the corn-to-butanol production process provide the basis for GREET modeling to estimate life-cycle energy use and greenhouse gas emissions. The GREET model was expanded to simulate the bio-butanol life cycle, from agricultural chemical production to butanol use in motor vehicles. We then compared the results for bio-butanol with those of conventional gasoline. We also analyzed the bio-acetone that is coproduced with bio-butanol as an alternative to petroleum-based acetone. Our study shows that, while the use of corn-based butanol achieves energy benefits and reduces greenhouse gas emissions, the results are affected by the methods used to treat the acetone that is co-produced in butanol plants.

Value Added Products from Hemicellulose Utilization in Dry Mill Ethanol Plants

Energy Technology Data Exchange (ETDEWEB)

Rodney Williamson, ICPB; John Magnuson, PNNL; David Reed, INL; Marco Baez, Dyadic; Marion Bradford, ICPB

2007-03-30

The Iowa Corn Promotion Board is the principal contracting entity for this grant funded by the US Department of Agriculture and managed by the US Department of Energy. The Iowa Corn Promotion Board subcontracted with New Jersey Institute of Technology, KiwiChem, Pacific Northwest National Lab and Idaho National Lab to conduct research for this project. KiwiChem conducted the economic engineering assessment of a dry-mill ethanol plant. New Jersey Institute of Technology conducted work on incorporating the organic acids into polymers. Pacific Northwest National Lab conducted work in hydrolysis of hemicellulose, fermentation and chemical catalysis of sugars to value-added chemicals. Idaho National Lab engineered an organism to ferment a specific organic acid. Dyadic, an enzme company, was a collaborator which provided in-kind support for the project. The Iowa Corn Promotion Board collaborated with the Ohio Corn Marketing Board and the Minnesota Corn Merchandising Council in providing cost share for the project. The purpose of this diverse collaboration was to integrate the hydrolysis, the conversion and the polymer applications into one project and increase the likelihood of success. This project had two primary goals: (1) to hydrolyze the hemicellulose fraction of the distillers grain (DG) coproduct coming from the dry-mill ethanol plants and (2) convert the sugars derived from the hemicellulose into value-added co-products via fermentation and chemical catalysis.

A practical method for extending the biuret assay to protein determination of corn-based products.

Science.gov (United States)

Liu, Zelong; Pan, Junhui

2017-06-01

A modified biuret method suitable for protein determination of corn-based products was developed by introducing a combination of an alkaline reagent with sodium dodecyl sulfate (reagent A) and heat treatments. The method was tested on seven corn-based samples. The results showed mostly good agreement (P>0.05) as compared to the Kjeldahl values. The proposed method was found to enhance the accuracy of prediction on zein content using bovine serum albumin as standard. Reagent A and sample treatment were proved to effectively improve protein solubilization for the thermally-dried corn-based products, e.g. corn gluten meal. The absorbance was stable for at least 1-h. Moreover, the whole measurement of protein content only needs 15-20min more than the traditional biuret assay, and can be performed in batches. The findings suggest that the proposed method could be a timesaving alternative for routine protein analyses in corn processing factories. Copyright © 2016 Elsevier Ltd. All rights reserved.

Valorization of lignin and cellulose in acid-steam-exploded corn stover by a moderate alkaline ethanol post-treatment based on an integrated biorefinery concept.

Science.gov (United States)

Yang, Sheng; Zhang, Yue; Yue, Wen; Wang, Wei; Wang, Yun-Yan; Yuan, Tong-Qi; Sun, Run-Cang

2016-01-01

Due to the unsustainable consumption of fossil resources, great efforts have been made to convert lignocellulose into bioethanol and commodity organic compounds through biological methods. The conversion of cellulose is impeded by the compactness of plant cell wall matrix and crystalline structure of the native cellulose. Therefore, appropriate pretreatment and even post-treatment are indispensable to overcome this problem. Additionally, an adequate utilization of coproduct lignin will be important for improving the economic viability of modern biorefinery industries. The effectiveness of moderate alkaline ethanol post-treatment on the bioconversion efficiency of cellulose in the acid-steam-exploded corn stover was investigated in this study. Results showed that an increase of the alcoholic sodium hydroxide (NaOH) concentration from 0.05 to 4% led to a decrease in the lignin content in the post-treated samples from 32.8 to 10.7%, while the cellulose digestibility consequently increased. The cellulose conversion of the 4% alcoholic NaOH integrally treated corn stover reached up to 99.3% after 72 h, which was significantly higher than that of the acid steam exploded corn stover without post-treatment (57.3%). In addition to the decrease in lignin content, an expansion of cellulose I lattice induced by the 4% alcoholic NaOH post-treatment played a significant role in promoting the enzymatic hydrolysis of corn stover. More importantly, the lignin fraction (AL) released during the 4% alcoholic NaOH post-treatment and the lignin-rich residue (EHR) remained after the enzymatic hydrolysis of the 4% alcoholic NaOH post-treated acid-steam-exploded corn stover were employed to synthesize lignin-phenol-formaldehyde (LPF) resins. The plywoods prepared with the resins exhibit satisfactory performances. An alkaline ethanol system with an appropriate NaOH concentration could improve the removal of lignin and modification of the crystalline structure of cellulose in acid

Quantifying cradle-to-farm gate life-cycle impacts associated with fertilizer used for corn, soybean, and stover production

Energy Technology Data Exchange (ETDEWEB)

Powers, Susan E. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2005-05-01

Fertilizer use can cause environmental problems, particularly eutrophication of water bodies from excess nitrogen or phosphorus. Increased fertilizer runoff is a concern for harvesting corn stover for ethanol production.

Grain and cellulosic ethanol: History, economics, and energy policy

International Nuclear Information System (INIS)

Solomon, Barry D.; Barnes, Justin R.; Halvorsen, Kathleen E.

2007-01-01

The United States (US) and Brazil have been the two leading producers of fuel ethanol since the 1970s. National policies have supported the production and use of ethanol from corn and sugarcane. US support in particular has included exemption from federal gasoline excise taxes, whole or partial exemption from road use (sales) taxes in nine states, a federal production tax credit, and a federal blender's credit. In the last decade the subsidization of grain-based ethanol has been increasingly criticized as economically inefficient and of questionable social benefit. In addition, much greater production of ethanol from corn may conflict with food production needs. A promising development is the acceleration of the technical readiness of cellulosic alcohol fuels, which can be produced from the woody parts of trees and plants, perennial grasses, or residues. This technology is now being commercialized and has greater long-term potential than grain ethanol. Cellulosic ethanol is projected to be much more cost-effective, environmentally beneficial, and have a greater energy output to input ratio than grain ethanol. The technology is being developed in North America, Brazil, Japan and Europe. In this paper, we will review the historical evolution of US federal and state energy policy support for and the currently attractive economics of the production and use of ethanol from biomass. The various energy and economic policies will be reviewed and assessed for their potential effects on cellulosic ethanol development relative to gasoline in the US. (author)

Bioenergy from stillage anaerobic digestion to enhance the energy balance ratio of ethanol production.

Science.gov (United States)

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

Continuous Ethanol Production Using Immobilized-Cell/Enzyme Biocatalysts in Fluidized-Bed Bioreactor (FBR)

Energy Technology Data Exchange (ETDEWEB)

Nghiem, NP

2003-11-16

The immobilized-cell fluidized-bed bioreactor (FBR) was developed at Oak Ridge National Laboratory (ORNL). Previous studies at ORNL using immobilized Zymomonas mobilis in FBR at both laboratory and demonstration scale (4-in-ID by 20-ft-tall) have shown that the system was more than 50 times as productive as industrial benchmarks (batch and fed-batch free cell fermentations for ethanol production from glucose). Economic analysis showed that a continuous process employing the FBR technology to produce ethanol from corn-derived glucose would offer savings of three to six cents per gallon of ethanol compared to a typical batch process. The application of the FBR technology for ethanol production was extended to investigate more complex feedstocks, which included starch and lignocellulosic-derived mixed sugars. Economic analysis and mathematical modeling of the reactor were included in the investigation. This report summarizes the results of these extensive studies.

Ethanol production in small- to medium-size facilities

Science.gov (United States)

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.

Increasing corn for biofuel production reduces biocontrol services in agricultural landscapes

NARCIS (Netherlands)

Landis, D.A.; Gardiner, M.M.; Werf, van der W.; Swinton, S.M.

2008-01-01

Increased demand for corn grain as an ethanol feedstock is altering U. S. agricultural landscapes and the ecosystem services they provide. From 2006 to 2007, corn acreage increased 19% nationally, resulting in reduced crop diversity in many areas. Biological control of insects is an ecosystem

Lignocellulosic ethanol production by starch-base industrial yeast under PEG detoxification

Science.gov (United States)

Liu, Xiumei; Xu, Wenjuan; Mao, Liaoyuan; Zhang, Chao; Yan, Peifang; Xu, Zhanwei; Zhang, Z. Conrad

2016-02-01

Cellulosic ethanol production from lignocellulosic biomass offers a sustainable solution for transition from fossil based fuels to renewable alternatives. However, a few long-standing technical challenges remain to be addressed in the development of an economically viable fermentation process from lignocellulose. Such challenges include the needs to improve yeast tolerance to toxic inhibitory compounds and to achieve high fermentation efficiency with minimum detoxification steps after a simple biomass pretreatment. Here we report an in-situ detoxification strategy by PEG exo-protection of an industrial dry yeast (starch-base). The exo-protected yeast cells displayed remarkably boosted vitality with high tolerance to toxic inhibitory compounds, and with largely improved ethanol productivity from crude hydrolysate derived from a pretreated lignocellulose. The PEG chemical exo-protection makes the industrial S. cerevisiae yeast directly applicable for the production of cellulosic ethanol with substantially improved productivity and yield, without of the need to use genetically modified microorganisms.

Fuel ethanol production from wet oxidised corn stover by S. cerevisiae

DEFF Research Database (Denmark)

Qiang, zhang; Thomsen, Anne Belinda

2012-01-01

of 74.6% were obtained after pretreatment. 86.5% of cellulose was remained in the solid cake. After 24h hydrolysis at 50°C using cellulase (Cellubrix L), the achieved conversion of cellulose to glucose was 64.8%. Ethanol production was evaluated from dried solid cake and the hydrolysate was employed...

Study of the production of ethanol from sugar beets for use as a motor fuel. Final report, February 1, 1980-April 30, 1981

Energy Technology Data Exchange (ETDEWEB)

Baird, H W

1981-04-27

This study was performed to assess the feasibility of producing fuel ethanol from sugar beets. Sugar beets are a major agricultural crop in the area and the beet sugar industry is a major employer. There have been some indications that increasing competition from imported sugar and fructose sugar produced from corn may lead to lower average sugar prices than have prevailed in the past. Fuel ethanol might provide an attractive alternative market for beets and ethanol production would continue to provide an industrial base for labor. Ethanol production from beets would utilize much of the same field and plant equipment as is now used for sugar. It is logical to examine the modification of an existing sugar plant from producing sugar to ethanol. The decision was made to use Great Western Sugar Company's plant at Mitchell as the example plant. This plant was selected primarily on the basis of its independence from other plants and the availability of relatively nearby beet acreage. The potential feedstocks assessed included sugar beets, corn, hybrid beets, and potatoes. Markets were assessed for ethanol and fermentation by-products saleability. Investment and operating costs were determined for each prospective plant. Plants were evaluated using a discounted cash flow technique to obtain data on full production costs. Environmental, health, safety, and socio-economic aspects of potential facilities were examined. Three consulting engineering firms and 3 engineering-construction firms are considered capable of providing the desired turn-key engineering design and construction services. It was concluded that the project is technically feasible. (DMC)

Starch hydrolysis modeling: application to fuel ethanol production.

Science.gov (United States)

Murthy, Ganti S; Johnston, David B; Rausch, Kent D; Tumbleson, M E; Singh, Vijay

2011-09-01

Efficiency of the starch hydrolysis in the dry grind corn process is a determining factor for overall conversion of starch to ethanol. A model, based on a molecular approach, was developed to simulate structure and hydrolysis of starch. Starch structure was modeled based on a cluster model of amylopectin. Enzymatic hydrolysis of amylose and amylopectin was modeled using a Monte Carlo simulation method. The model included the effects of process variables such as temperature, pH, enzyme activity and enzyme dose. Pure starches from wet milled waxy and high-amylose corn hybrids and ground yellow dent corn were hydrolyzed to validate the model. Standard deviations in the model predictions for glucose concentration and DE values after saccharification were less than ± 0.15% (w/v) and ± 0.35%, respectively. Correlation coefficients for model predictions and experimental values were 0.60 and 0.91 for liquefaction and 0.84 and 0.71 for saccharification of amylose and amylopectin, respectively. Model predictions for glucose (R2 = 0.69-0.79) and DP4+ (R2 = 0.8-0.68) were more accurate than the maltotriose and maltose for hydrolysis of high-amylose and waxy corn starch. For yellow dent corn, simulation predictions for glucose were accurate (R2 > 0.73) indicating that the model can be used to predict the glucose concentrations during starch hydrolysis.

Integrated Process for Extraction of Wax as a Value-Added Co-Product and Improved Ethanol Production by Converting Both Starch and Cellulosic Components in Sorghum Grains

Directory of Open Access Journals (Sweden)

Nhuan P. Nghiem

2018-02-01

Full Text Available Grain sorghum is a potential feedstock for fuel ethanol production due to its high starch content, which is equivalent to that of corn, and has been successfully used in several commercial corn ethanol plants in the United States. Some sorghum grain varieties contain significant levels of surface wax, which may interact with enzymes and make them less efficient toward starch hydrolysis. On the other hand, wax can be recovered as a valuable co-product and as such may help improve the overall process economics. Sorghum grains also contain lignocellulosic materials in the hulls, which can be converted to additional ethanol. An integrated process was developed, consisting of the following steps: 1. Extraction of wax with boiling ethanol, which is the final product of the proposed process; 2. Pretreatment of the dewaxed grains with dilute sulfuric acid; 3. Mashing and fermenting of the pretreated grains to produce ethanol. During the fermentation, commercial cellulase was also added to release fermentable sugars from the hulls, which then were converted to additional ethanol. The advantages of the developed process were illustrated with the following results: (1 Wax extracted (determined by weight loss: ~0.3 wt % of total mass. (2 Final ethanol concentration at 25 wt % solid using raw grains: 86.1 g/L. (3 Final ethanol concentration at 25 wt % solid using dewaxed grains: 106.2 g/L (23.3% improvement. (4 Final ethanol concentration at 25 wt % solid using dewaxed and acid-treated grains (1 wt % H2SO4 plus cellulase (CTec2: 117.8 g/L (36.8% improvement.

Policy Uncertainty and the US Ethanol Industry

Directory of Open Access Journals (Sweden)

Jason P. H. Jones

2017-11-01

Full Text Available The Renewable Fuel Standard (RFS2, as implemented, has introduced uncertainty into US ethanol producers and the supporting commodity market. First, the fixed mandate for what is mainly cornstarch-based ethanol has increased feedstock price volatility and exerts a general effect across the agricultural sector. Second, the large discrepancy between the original Energy Independence and Security Act (EISA intentions and the actual RFS2 implementation for some fuel classes has increased the investment uncertainty facing investors in biofuel production, distribution, and consumption. Here we discuss and analyze the sources of uncertainty and evaluate the effect of potential RFS2 adjustments as they influence these uncertainties. This includes the use of a flexible, production dependent mandate on corn starch ethanol. We find that a flexible mandate on cornstarch ethanol relaxed during drought could significantly reduce commodity price spikes and alleviate the decline of livestock production in cases of feedstock production shortfalls, but it would increase the risk for ethanol investors.

Periodic peristalsis increasing acetone-butanol-ethanol productivity during simultaneous saccharification and fermentation of steam-exploded corn straw.

Science.gov (United States)

Li, Jingwen; Wang, Lan; Chen, Hongzhang

2016-11-01

The acetone-butanol-ethanol (ABE) fermentation of lignocellulose at high solids content has recently attracted extensive attention. However, the productivity of high solids ABE fermentation of lignocellulose is typically low in traditional processes due to the lack of efficient intensifying methods. In the present study, periodic peristalsis, a novel intensifying method, was applied to improve ABE production by the simultaneous saccharification and fermentation (SSF) of steam-exploded corn straw using Clostridium acetobutylicum ATCC824. The ABE concentration and the ABE productivity of SSF at a solids content of 17.5% (w/w) with periodic peristalsis were 17.1 g/L and 0.20 g/(L h), respectively, which were higher than those obtained under static conditions (15.2 g/L and 0.14 g/(L h)). The initial sugar conversion rate over the first 12 h with periodic peristalsis was 4.67 g/(L h) at 10 FPU/g cellulase dosage and 15% (w/w) solids content, an increase of 49.7% compared with the static conditions. With periodic peristalsis, the period of batch fermentation was shortened from 108 h to 84 h. The optimal operating regime was a low frequency (6 h -1 ) of periodic peristalsis in the acid-production phase (0-48 h) of SSF. Therefore, periodic peristalsis should be an effective intensifying method to increase the productivity of ABE fermentation at high solids content. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Biochemical Disincentives to Fertilizing Cellulosic Ethanol Crops

Science.gov (United States)

Gallagher, M. E.; Hockaday, W. C.; Snapp, S.; McSwiney, C.; Baldock, J.

2010-12-01

Corn grain biofuel crops produce the highest yields when the cropping ecosystem is not nitrogen (N)-limited, achieved by application of fertilizer. There are environmental consequences for excessive fertilizer application to crops, including greenhouse gas emissions, hypoxic “dead zones,” and health problems from N runoff into groundwater. The increase in corn acreage in response to demand for alternative fuels (i.e. ethanol) could exacerbate these problems, and divert food supplies to fuel production. A potential substitute for grain ethanol that could reduce some of these impacts is cellulosic ethanol. Cellulosic ethanol feedstocks include grasses (switchgrass), hardwoods, and crop residues (e.g. corn stover, wheat straw). It has been assumed that these feedstocks will require similar N fertilization rates to grain biofuel crops to maximize yields, but carbohydrate yield versus N application has not previously been monitored. We report the biochemical stocks (carbohydrate, protein, and lignin in Mg ha-1) of a corn ecosystem grown under varying N levels. We measured biochemical yield in Mg ha-1 within the grain, leaf and stem, and reproductive parts of corn plants grown at seven N fertilization rates (0-202 kg N ha-1), to evaluate the quantity and quality of these feedstocks across a N fertilization gradient. The N fertilization rate study was performed at the Kellogg Biological Station-Long Term Ecological Research Site (KBS-LTER) in Michigan. Biochemical stocks were measured using 13C nuclear magnetic resonance spectroscopy (NMR), combined with a molecular mixing model (Baldock et al. 2004). Carbohydrate and lignin are the main biochemicals of interest in ethanol production since carbohydrate is the ethanol feedstock, and lignin hinders the carbohydrate to ethanol conversion process. We show that corn residue carbohydrate yields respond only weakly to N fertilization compared to grain. Grain carbohydrate yields plateau in response to fertilization at

Well-to-wake analysis of ethanol-to-jet and sugar-to-jet pathways.

Science.gov (United States)

Han, Jeongwoo; Tao, Ling; Wang, Michael

2017-01-01

To reduce the environmental impacts of the aviation sector as air traffic grows steadily, the aviation industry has paid increasing attention to bio-based alternative jet fuels (AJFs), which may provide lower life-cycle petroleum consumption and greenhouse gas (GHG) emissions than petroleum jet fuel. This study presents well-to-wake (WTWa) results for four emerging AJFs: ethanol-to-jet (ETJ) from corn and corn stover, and sugar-to-jet (STJ) from corn stover via both biological and catalytic conversion. For the ETJ pathways, two plant designs were examined: integrated (processing corn or corn stover as feedstock) and distributed (processing ethanol as feedstock). Also, three H 2 options for STJ via catalytic conversion are investigated: external H 2 from natural gas (NG) steam methane reforming (SMR), in situ H 2 , and H 2 from biomass gasification. Results demonstrate that the feedstock is a key factor in the WTWa GHG emissions of ETJ: corn- and corn stover-based ETJ are estimated to produce WTWa GHG emissions that are 16 and 73%, respectively, less than those of petroleum jet. As for the STJ pathways, this study shows that STJ via biological conversion could generate WTWa GHG emissions 59% below those of petroleum jet. STJ via catalytic conversion could reduce the WTWa GHG emissions by 28% with H 2 from NG SMR or 71% with H 2 from biomass gasification than those of petroleum jet. This study also examines the impacts of co-product handling methods, and shows that the WTWa GHG emissions of corn stover-based ETJ, when estimated with a displacement method, are lower by 11 g CO 2 e/MJ than those estimated with an energy allocation method. Corn- and corn stover-based ETJ as well as corn stover-based STJ show potentials to reduce WTWa GHG emissions compared to petroleum jet. Particularly, WTWa GHG emissions of STJ via catalytic conversion depend highly on the hydrogen source. On the other hand, ETJ offers unique opportunities to exploit extensive existing corn ethanol

Granular starch hydrolysis for fuel ethanol production

Science.gov (United States)

Wang, Ping

addition were evaluated in the dry grind process using GSHE (GSH process). Addition of proteases resulted in higher ethanol concentrations (15.2 to 18.0% v/v) and lower (DDGS) yields (32.9 to 45.8% db) compared to the control (no protease addition). As level of proteases and GSHE increased, ethanol concentrations increased and DDGS yields decreased. Proteases addition reduced required GSHE dose. Ethanol concentrations with protease addition alone were higher than with urea or with addition of both protease and urea. Corn endosperm consists of soft and hard endosperm. More exposed starch granules and rough surfaces produced from soft endosperm compared to hard endosperm will create more surface area which will benefit the solid phase hydrolysis as used in GSH process. In this study, the effects of protease, urea, endosperm hardness and GSHE levels on the GSH process were evaluated. Soft and hard endosperm materials were obtained by grinding and sifting flaking grits from dry milling pilot plant. Soft endosperm resulted in higher ethanol concentrations (at 72 hr) compared to ground corn or hard endosperm. Addition of urea increased ethanol concentrations (at 72 hr) for soft and hard endosperm. The effect of protease addition on increasing ethanol concentrations and fermentation rates was more predominant for soft endosperm, less for hard endosperm and least for ground corn. The GSH process with protease resulted in higher ethanol concentration than that with urea. For fermentation of soft endosperm, GSHE dose can be reduced. Ground corn fermented faster at the beginning than hard and soft endosperm due to the presence of inherent nutrients which enhanced yeast growth.

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

Science.gov (United States)

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

2015-05-01

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

Ethanol production from biomass by repetitive solid-state fed-batch fermentation with continuous recovery of ethanol

Energy Technology Data Exchange (ETDEWEB)

Moukamnerd, Churairat; Kino-oka, Masahiro; Sugiyama, Minetaka; Kaneko, Yoshinobu; Harashima, Satoshi; Katakura, Yoshio [Osaka Univ. (Japan). Dept. of Biotechnology; Boonchird, Chuenchit [Mahidol Univ., Bangkok (Thailand). Dept. of Biotechnology; Noda, Hideo [Kansai Chemical Engineering Co., Ltd., Amagasaki (Japan); Ninomiya, Kazuaki [Kanazawa Univ. (Japan). Inst. of International Environment Technology; Shioya, Suteaki [Sojo Univ., Kumamoto (Japan). Dept. of Applied Life Science

2010-09-15

To save cost and input energy for bioethanol production, a consolidated continuous solid-state fermentation system composed of a rotating drum reactor, a humidifier, and a condenser was developed. Biomass, saccharifying enzymes, yeast, and a minimum amount of water are introduced into the system. Ethanol produced by simultaneous saccharification and fermentation is continuously recovered as vapor from the headspace of the reactor, while the humidifier compensates for the water loss. From raw corn starch as a biomass model, 95 {+-} 3, 226 {+-} 9, 458 {+-} 26, and 509 {+-} 64 g l{sup -1} of ethanol solutions were recovered continuously when the ethanol content in reactor was controlled at 10-20, 30-50, 50-70 and 75-85 g kg-mixture{sup -1}, respectively. The residue showed a lesser volume and higher solid content than that obtained by conventional liquid fermentation. The cost and energy for intensive waste water treatment are decreased, and the continuous fermentation enabled the sustainability of enzyme activity and yeast in the system. (orig.)

Composition of corn dry-grind ethanol by-products: DDGS, wet cake, and thin stillage.

Science.gov (United States)

Kim, Youngmi; Mosier, Nathan S; Hendrickson, Rick; Ezeji, Thaddeus; Blaschek, Hans; Dien, Bruce; Cotta, Michael; Dale, Bruce; Ladisch, Michael R

2008-08-01

DDGS and wet distillers' grains are the major co-products of the dry grind ethanol facilities. As they are mainly used as animal feed, a typical compositional analysis of the DDGS and wet distillers' grains mainly focuses on defining the feedstock's nutritional characteristics. With an increasing demand for fuel ethanol, the DDGS and wet distillers' grains are viewed as a potential bridge feedstock for ethanol production from other cellulosic biomass. The introduction of DDGS or wet distillers' grains as an additional feed to the existing dry grind plants for increased ethanol yield requires a different approach to the compositional analysis of the material. Rather than focusing on its nutritional value, this new approach aims at determining more detailed chemical composition, especially on polymeric sugars such as cellulose, starch and xylan, which release fermentable sugars upon enzymatic hydrolysis. In this paper we present a detailed and complete compositional analysis procedure suggested for DDGS and wet distillers' grains, as well as the resulting compositions completed by three different research groups. Polymeric sugars, crude protein, crude oil and ash contents of DDGS and wet distillers' grains were accurately and reproducibly determined by the compositional analysis procedure described in this paper.

Availability of crop cellulosics for ethanol production

Energy Technology Data Exchange (ETDEWEB)

Hayes, R.D.

1982-10-01

Past estimates of cellulosic resources available from Canadian agriculture totalled over 23 million tonnes of cereal grain straw and corn stover residues surplus to soil and animal requirements. A new much reduced estimate, based on four detailed regional studies that also include previously unassessed resources such as chaff, oilseed hulls, and food processing wastes, is suggested. Eleven million tonnes are currently available from all residue sources for energy conversion by different processes. Only five million tonnes are identified as potentially usable in ethanol production plants were they to be constructed. Additional resource opportunities may become available in future from currently underutilized land, especially saline soils, novel processing techniques of conventional grains and forages, innovative cropping systems that may increase the yield of agricultural biomass, and new food/feed/fuel (i.e. multi-purpose) crops such as kochia, milkweed, and Jerusalem artichoke. 27 refs., 1 fig., 1 tab.

Potassium sorbate reduces production of ethanol and 2 esters in corn silage

DEFF Research Database (Denmark)

Hafner, Sasha; Franco, Roberta B; Kung, Limin

2014-01-01

concentrations within silage were measured after ensiling and sample storage using a headspace gas chromatography method. The high dose of potassium sorbate was the only treatment that inhibited the production of multiple VOC. Compared with the control response, it reduced ethanol by 58%, ethyl acetate by 46...

Feasibility assessment of whey-based ethanol facilities

Energy Technology Data Exchange (ETDEWEB)

Walker, L P; Pellerin, R A; Rao, A M; Hang, Y D; Kalter, R J; Boisvert, R N; Gabler, E C

1985-07-01

In the U.S., corn has been the principal commodity considered for conversion to ethanol. One alternative to using corn and other food crops is to utilize organic wastes, such as food processing waste. Cheese whey is one such waste that holds potential for conversion to ethanol. To ascertain the feasibility of using whey as a feedstock a series of regional studies were conducted by the authors. Results from these studies indicate that the transport of condensed whey to a central processing plant for conversion to ethanol is economically feasible. The energy balance for the plants considered can yield a positive or negative balance depending on whether an energy penalty is assigned for condensing the whey. A net energy gain of 23833 to 26921 kJ/l of ethanol was obtained if energy for whey condensing was not included and a net energy loss ranging from -279 to -686 kJ/l was obtained if whey condensing was included in the energy balance. Plants utilizing continuous fermentation technology showed positive energy balance with or without a penalty for the condensing of the whey.

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

Science.gov (United States)

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

Preliminary investigation into the pressing process of sweet pearl millet and sweet sorghum biomass for ethanol production

Energy Technology Data Exchange (ETDEWEB)

Crepeau, M.; Khelifi, M.; Vanasse, A. [Laval Univ., Quebec City, PQ (Canada). Dept. of Soil Science and Agri-Food Engineering

2010-07-01

Corn is the main source for biofuel production in North America. However, both sweet pearl millet and sweet sorghum crops represent an interesting alternative to corn for ethanol production because of their high biomass yield under a wide range of environmental conditions and high concentration of readily fermentable sugars. Coproducts such as pressing residues can be also be utilized so that nothing is lost in the process. However, in order to improve the extraction of juice for ethanol production, the pressing process of this biomass must be optimized. Preliminary experiments were therefore conducted to optimize the juice extraction from sweet pearl millet and sweet sorghum using 2 different presses, notably a screw press and a manually operated hydraulic press. Both types of biomass were either chopped finely or coarsely and were exposed to various pressures with the hydraulic press. The volume of juice extracted from both crops increased linearly with increasing pressure. Sweet sorghum appeared to be a better feedstock for ethanol production because it produced about 0.03 to 0.06 litre of juice per kg of biomass more than sweet pearl millet. Juice extraction was more effective with the screw press, but only a small difference was noted between the 2 chopping modes.

Dye-sensitized solar cells based on purple corn sensitizers

International Nuclear Information System (INIS)

Phinjaturus, Kawin; Maiaugree, Wasan; Suriharn, Bhalang; Pimanpaeng, Samuk; Amornkitbamrung, Vittaya; Swatsitang, Ekaphan

2016-01-01

Graphical abstract: - Highlights: • Extract from husk, cob and silk of purple corn was used as a photosensitizer in DSSC. • Effect of solvents i.e. acetone, ethanol and DI water on DSSC efficiency was studied. • The highest efficiency of 1.06% was obtained in DSSC based on acetone extraction. - Abstract: Natural dye extracted from husk, cob and silk of purple corn, were used for the first time as photosensitizers in dye sensitized solar cells (DSSCs). The dye sensitized solar cells fabrication process has been optimized in terms of solvent extraction. The resulting maximal efficiency of 1.06% was obtained from purple corn husk extracted by acetone. The ultraviolet–visible (UV–vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and incident photon-to-current efficiency (IPCE) were employed to characterize the natural dye and the DSSCs.

Dye-sensitized solar cells based on purple corn sensitizers

Energy Technology Data Exchange (ETDEWEB)

Phinjaturus, Kawin [Materials Science and Nanotechnology Program, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Maiaugree, Wasan [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Suriharn, Bhalang [Department of Plant Science and Agricultural Resources, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002 (Thailand); Pimanpaeng, Samuk; Amornkitbamrung, Vittaya [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Integrated Nanotechnology Research Center (INRC), Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Swatsitang, Ekaphan, E-mail: ekaphan@kku.ac.th [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Integrated Nanotechnology Research Center (INRC), Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Nanotec-KKU Center of Excellence on Advanced Nanomaterials for Energy Production and Storage, Khon Kaen 40002 (Thailand)

2016-09-01

Graphical abstract: - Highlights: • Extract from husk, cob and silk of purple corn was used as a photosensitizer in DSSC. • Effect of solvents i.e. acetone, ethanol and DI water on DSSC efficiency was studied. • The highest efficiency of 1.06% was obtained in DSSC based on acetone extraction. - Abstract: Natural dye extracted from husk, cob and silk of purple corn, were used for the first time as photosensitizers in dye sensitized solar cells (DSSCs). The dye sensitized solar cells fabrication process has been optimized in terms of solvent extraction. The resulting maximal efficiency of 1.06% was obtained from purple corn husk extracted by acetone. The ultraviolet–visible (UV–vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and incident photon-to-current efficiency (IPCE) were employed to characterize the natural dye and the DSSCs.

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

Science.gov (United States)

Wilhelm, W. W.; Cushman, J.

2003-12-01

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

Handling Indian corn on the cob (for the alcohol industry)

Energy Technology Data Exchange (ETDEWEB)

Podurazhnyi, Y K

1962-01-01

The corn grains are mechanically prepared from the cob shortly before malting, the wort is boiled at 142 to 144/sup 0/, and is made up of corn 34, beets 40, and molasses 26%, providing an alcohol liquor which contains on the average 7.34% (individual values as high as 8.6) ethanol. This application of corn on the cob incurs (on the base of prices in the Soviet Union) a saving of about 20% in ethanol manufacture.

Does Integration Help Adapt to Climate Change? Case of Increased US Corn Yield Volatility

Science.gov (United States)

Verma, M.; Diffenbaugh, N. S.; Hertel, T. W.

2012-12-01

In absence of of new crop varieties or significant shifts in the geography of corn production, US national corn yields variation could double by the year 2040 as a result of climate change and without adaptation this could lead the variability in US corn prices to quadruple (Diffenbaugh et al. 2012). In addition to climate induced price changes, analysis of recent commodity price spikes suggests that interventionist trade policies are partly to blame. Assuming we cannot much influence the future climate outcome, what policies can we undertake to adapt better? Can we use markets to blunt this edge? Diffenbaugh et al. find that sale of corn- ethanol for use in liquid fuel, when governed by quotas such as US Renewable Fuel Standard (RFS), could make US corn prices even more variable; in contrast the same food-fuel market link (we refer to it as intersectoral link) may well dampen price volatility when the sale of corn to ethanol industry is driven by higher future oil prices. The latter however comes at the cost of exposing corn prices to the greater volatility in oil markets. Similarly intervention in corn trade can make US corn prices less or more volatile by distorting international corn price transmission. A negative US corn yield shock shows that domestic corn supply falls and domestic prices to go up irrespective of whether or not markets are integrated. How much the prices go up depends on how much demand adjusts to accommodate the supply shock. Based on the forgoing analysis, one should expect that demand would adjust more readily when markets are integrated and therefore reduce the resulting price fluctuation. Simulation results confirm this response of corn markets. In terms of relative comparisons however a policy driven intersectoral integration is least effective and prices rise much more. Similarly, a positive world oil price shock makes the US oil imports expensive and with oil being used to produce gasoline blends, it increases the price of gasoline

Ethanol from wood. Cellulase enzyme production

Energy Technology Data Exchange (ETDEWEB)

Szengyel, Zsolt

2000-03-01

Conversion of biomass to liquid fuels, such as ethanol, has been investigated during the past decades. First due to the oil crisis of the 1970s and lately because of concerns about greenhouse effect, ethanol has been found to be a suitable substitute for gasoline in transportation. Although ethanol is produced in large quantities from corn starch, the conversion of lignocellulosic biomass to ethanol is rather problematic. However, cellulosic raw materials are important as they are available in large quantities from agriculture and forestry. One of the most extensively investigated processes is the enzymatic process, in which fungal cellulolytic enzymes are used to convert the cellulose content of the biomass to glucose, which is then fermented to ethanol. In order to make the raw material accessible to biological attack, it has to be pretreated first. The most successful method, which has been evaluated for various lignocellulosic materials, is the steam pretreatment. In this thesis the utilization of steam pretreated willow (hardwood) and spruce (softwood) was examined for enzyme production using a filamentous fungus T. reesei RUT C30. Various carbon sources originating from the steam pretreated materials have been investigated. The replacement of the solid carbon source with a liquid carbon source, as well as the effect of pH, was studied. The effect of toxic compounds generated during pretreatment was also examined. Comparative study of softwood and hardwood showed that steam pretreated hardwood is a better carbon source than softwood. The hydrolytic potential of enzyme solutions produced on wood derived carbon sources was better compared to commercial cellulases. Also enzyme solutions produced on steam pretreated spruce showed less sensitivity towards toxic compounds formed during steam pretreatment.

Presence and biological activity of antibiotics used in fuel ethanol and corn co-product production.

Science.gov (United States)

Compart, D M Paulus; Carlson, A M; Crawford, G I; Fink, R C; Diez-Gonzalez, F; Dicostanzo, A; Shurson, G C

2013-05-01

Antibiotics are used in ethanol production to control bacteria from competing with yeast for nutrients during starch fermentation. However, there is no published scientific information on whether antibiotic residues are present in distillers grains (DG), co-products from ethanol production, or whether they retain their biological activity. Therefore, the objectives of this study were to quantify concentrations of various antibiotic residues in DG and determine whether residues were biologically active. Twenty distillers wet grains and 20 distillers dried grains samples were collected quarterly from 9 states and 43 ethanol plants in the United States. Samples were analyzed for DM, CP, NDF, crude fat, S, P, and pH to describe the nutritional characteristics of the samples evaluated. Samples were also analyzed for the presence of erythromycin, penicillin G, tetracycline, tylosin, and virginiamycin M1, using liquid chromatography and mass spectrometry. Additionally, virginiamycin residues were determined, using a U.S. Food and Drug Administration-approved bioassay method. Samples were extracted and further analyzed for biological activity by exposing the sample extracts to 10(4) to 10(7) CFU/mL concentrations of sentinel bacterial strains Escherichia coli ATCC 8739 and Listeria monocytogenes ATCC 19115. Extracts that inhibited bacterial growth were considered to have biological activity. Physiochemical characteristics varied among samples but were consistent with previous findings. Thirteen percent of all samples contained low (≤1.12 mg/kg) antibiotic concentrations. Only 1 sample extract inhibited growth of Escherichia coli at 10(4) CFU/mL, but this sample contained no detectable concentrations of antibiotic residues. No extracts inhibited Listeria monocytogenes growth. These data indicate that the likelihood of detectable concentrations of antibiotic residues in DG is low; and if detected, they are found in very low concentrations. The inhibition in only 1 DG

Efficiency in Midwest US corn ethanol plants: A plant survey

International Nuclear Information System (INIS)

Perrin, Richard K.; Fretes, Nickolas F.; Sesmero, Juan Pablo

2009-01-01

Continuation of policy support for the US corn ethanol industry is being debated due to doubts about the greenhouse gas effects of the industry and the effects of the industry on food prices. Yet there is no publicly available data on the economic and technical performance of the current generation of plants, which constitute the overwhelming majority of the industry. This study helps to fill that gap. Seven recently constructed ethanol plants in seven Midwest US states provided details on input requirements and operating costs during 2006 and 2007. Results show that technical performance is substantially better than current estimates available in the literature. Average net operating returns exceeded capital costs during the survey period, but price changes by mid-2008 reduced these margins to near zero. While the economic performance of the industry is currently viable, this study demonstrates that it can be threatened by current price trends, and certainly would be in the absence of current subsidies

Modification of Corn Starch Ethanol Refinery to Efficiently Accept Various High-Impact Cellulosic Feedstocks

Energy Technology Data Exchange (ETDEWEB)

Derr, Dan [Logos Technologies, Fairfax, VA (United States)

2013-12-30

The goal of the Corn-to-Cellulosic Migration (CCM) pilot facility was to demonstrate the implementation of advanced technologies and methods for conversion of non-food, cellulosic feedstocks into ethanol, assess the economics of the facility and evaluate potential environmental benefits for biomass to fuels conversion. The CCM project was comprised of design, build, and operate phases for the CCM pilot facility as well as research & development, and modeling components. The CCM pilot facility was designed to process 1 tonne per day of non-food biomass and biologically convert that biomass to ethanol at a rate of 70 gallons per tonne. The plant demonstrated throughputs in excess of 1 tonne per day for an extended run of 1400 hours. Although target yields were not fully achieved, the continuous operation validated the design and operability of the plant. These designs will permit the design of larger scale operations at existing corn milling operations or for greenfield plants. EdeniQ, a partner in the project and the owner of the pilot plant, continues to operate and evaluate other feedstocks.

Agricultural sector impacts of making ethanol from grain

Energy Technology Data Exchange (ETDEWEB)

Hertzmark, D.; Ray, D.; Parvin, G.

1980-03-01

This report presents the results of a model of the effects on the agricultural sector of producing ethanol from corn in the United States between 1979 and 1983. The model is aggregated at the national level, and results are given for all of the major food and feed crops, ethanol joint products, farm income, government payment, and agricultural exports. A stochastic simulation was performed to ascertain the impacts of yield and demand variations on aggregate performance figures. Results indicate minimal impacts on the agricultural sector for production levels of less than 1 billion gallons of ethanol per year. For higher production levels, corn prices will rise sharply, the agricultural sector will be more vulnerable to variations in yields and demands, and joint-product values will fall. Possibilities for ameliorating such effects are discussed, and such concepts as net energy and the biomass refinery are explored.

Comparison of several ethanol productions using xylanase, inorganic salts, surfactant

Science.gov (United States)

Wu, Yan; Lu, Jie; Yang, Rui-feng; Song, Wen-jing; Li, Hai-ming; Wang, Hai-song; Zhou, Jing-hui

2017-03-01

Liquid hot water (LHW) pretreatment is an effective and environmentally friendly method to produce bioethanol with lignocellulosic materials. Corn stover was pretreated with liquid hot water (LHW) and then subjected to semi-simultaneous saccharification and fermentation (S-SSF) to obtain high ethanol concentration and yield. The present study aimed to confirm the effect of several additives on the fermentation digestibility of unwashed WIS of corn stover pretreated with LHW. So we also investigated the process, such as enzyme addition, inorganic salts, surfactant and different loading Triton. Results show that high ethanol concentration is necessary to add xylanase in the stage of saccharification. The ethanol concentration increased mainly with magnesium ion on fermentation. Comparing with Tween 80, Span 80 and Polyethylene glycol, Triton is the best surfactant. In contrast to using xylanase and Triton respectively, optimization can make up the lack of stamina and improve effect of single inorganic salts.

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

Energy Technology Data Exchange (ETDEWEB)

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. This 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.

On the use of differential solubility in aqueous ethanol solutions to narrow the DP range of food-grade starch hydrolysis products.

Science.gov (United States)

Balto, Amy S; Lapis, Trina J; Silver, Rachel K; Ferreira, Andrew J; Beaudry, Christopher M; Lim, Juyun; Penner, Michael H

2016-04-15

Considerable research is focused on understanding the functionality of starch hydrolysis products (SHP) consisting of glucose, maltose, maltooligosaccharides (MOS), and maltopolysaccharides (MPS). A confounding factor in this research is the high molecular dispersity of commercially available SHP. The study presented herein characterizes a flexible fractionation approach for lowering the dispersity of such products. This was accomplished by fractionating a corn syrup solids (CSS) preparation based on the differential solubility of its component saccharides in aqueous-ethanol solutions. Products obtained from selected fractionations were characterized with respect to degree of polymerization (DP; liquid chromatography), dextrose equivalency (reducing sugar assays), and prevalence of branching (NMR). Glucose and maltose were preferentially removed from CSS using high (⩾90%) ethanol extractants. Preparations with relatively narrow ranges of MOS, lower DP MPS, and higher DP MPS were obtained through repetitive 70%-ethanol extractions. Linear, as opposed to branched, MOS and MPS were preferentially extracted under all conditions tested. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pectin-rich biomass as feedstock for fuel ethanol production.

Science.gov (United States)

Edwards, Meredith C; Doran-Peterson, Joy

2012-08-01

The USA has proposed that 30 % of liquid transportation fuel be produced from renewable resources by 2030 (Perlack and Stokes 2011). It will be impossible to reach this goal using corn kernel-based ethanol alone. Pectin-rich biomass, an under-utilized waste product of the sugar and juice industry, can augment US ethanol supplies by capitalizing on this already established feedstock. Currently, pectin-rich biomass is sold (at low value) as animal feed. This review focuses on the three most studied types of pectin-rich biomass: sugar beet pulp, citrus waste and apple pomace. Fermentations of these materials have been conducted with a variety of ethanologens, including yeasts and bacteria. Escherichia coli can ferment a wide range of sugars including galacturonic acid, the primary component of pectin. However, the mixed acid metabolism of E. coli can produce unwanted side products. Saccharomyces cerevisiae cannot naturally ferment galacturonic acid nor pentose sugars but has a homoethanol pathway. Erwinia chrysanthemi is capable of degrading many of the cell wall components of pectin-rich materials, including pectin. Klebsiella oxytoca can metabolize a diverse array of sugars including cellobiose, one degradation product of cellulose. However, both E. chrysanthemi and K. oxytoca produce side products during fermentation, similar to E. coli. Using pectin-rich residues from industrial processes is beneficial because the material is already collected and partially pretreated to facilitate enzymatic deconstruction of the plant cell walls. Using biomass already produced for other purposes is an attractive practice because fewer greenhouse gases (GHG) will be anticipated from land-use changes.

Pectin-rich biomass as feedstock for fuel ethanol production

Energy Technology Data Exchange (ETDEWEB)

Edwards, Meredith C.; Doran-Peterson, Joy [Georgia Univ., Athens, GA (United States). Dept. of Microbiology

2012-08-15

The USA has proposed that 30 % of liquid transportation fuel be produced from renewable resources by 2030 (Perlack and Stokes 2011). It will be impossible to reach this goal using corn kernel-based ethanol alone. Pectin-rich biomass, an under-utilized waste product of the sugar and juice industry, can augment US ethanol supplies by capitalizing on this already established feedstock. Currently, pectin-rich biomass is sold (at low value) as animal feed. This review focuses on the three most studied types of pectin-rich biomass: sugar beet pulp, citrus waste and apple pomace. Fermentations of these materials have been conducted with a variety of ethanologens, including yeasts and bacteria. Escherichia coli can ferment a wide range of sugars including galacturonic acid, the primary component of pectin. However, the mixed acid metabolism of E. coli can produce unwanted side products. Saccharomyces cerevisiae cannot naturally ferment galacturonic acid nor pentose sugars but has a homoethanol pathway. Erwinia chrysanthemi is capable of degrading many of the cell wall components of pectin-rich materials, including pectin. Klebsiella oxytoca can metabolize a diverse array of sugars including cellobiose, one degradation product of cellulose. However, both E. chrysanthemi and K. oxytoca produce side products during fermentation, similar to E. coli. Using pectin-rich residues from industrial processes is beneficial because the material is already collected and partially pretreated to facilitate enzymatic deconstruction of the plant cell walls. Using biomass already produced for other purposes is an attractive practice because fewer greenhouse gases (GHG) will be anticipated from land-use changes. (orig.)

The cost of ethanol production from lignocellulosic biomass -- A comparison of selected alternative processes. Final report

Energy Technology Data Exchange (ETDEWEB)

Grethlein, H.E.; Dill, T.

1993-04-30

The purpose of this report is to compare the cost of selected alternative processes for the conversion of lignocellulosic biomass to ethanol. In turn, this information will be used by the ARS/USDA to guide the management of research and development programs in biomass conversion. The report will identify where the cost leverages are for the selected alternatives and what performance parameters need to be achieved to improve the economics. The process alternatives considered here are not exhaustive, but are selected on the basis of having a reasonable potential in improving the economics of producing ethanol from biomass. When other alternatives come under consideration, they should be evaluated by the same methodology used in this report to give fair comparisons of opportunities. A generic plant design is developed for an annual production of 25 million gallons of anhydrous ethanol using corn stover as the model substrate at $30/dry ton. Standard chemical engineering techniques are used to give first order estimates of the capital and operating costs. Following the format of the corn to ethanol plant, there are nine sections to the plant; feed preparation, pretreatment, hydrolysis, fermentation, distillation and dehydration, stillage evaporation, storage and denaturation, utilities, and enzyme production. There are three pretreatment alternatives considered: the AFEX process, the modified AFEX process (which is abbreviated as MAFEX), and the STAKETECH process. These all use enzymatic hydrolysis and so an enzyme production section is included in the plant. The STAKETECH is the only commercially available process among the alternative processes.

Innovative inexpensive ethanol

International Nuclear Information System (INIS)

Mackek, S.

1991-01-01

New Energy Company of Indiana which produces 70 million gallons of ethanol per year, avoids the headaches often associated with organic by-products by creating an efficient and profitable sideline business. This paper reports that stretching across 55 acres in South Bend, Ind., New Energy's plant is the largest in the U.S. built specifically for fuel alcohol. The $186-million complex is a dramatic advance in the art of producing ethanol and its co-products. As the demand grows in the coming years for fuel alcohol-proven as an octane booster and a clean-burning alternative fuel. New Energy looks forward to increase production and profits. At the company's six-year-old plant, fuel alcohol is made from 26 million bushels a year of No. 2 yellow dent corn. Left at the bottom of the first column, after the alcohol has been boiled off, is stillage that contains more than 90% of the corn's protein and fat content, and virtually all of its vitamins and minerals, along with the yeast used to make the ethanol. While technically a waste product of the fuel alcohol process, this material's quantity and organic content not only make it difficult and costly to dispose, but its nutritional quality makes it an excellent candidate to be further processed into animal feed

Techno-economic analysis of corn stover fungal fermentation to ethanol

Energy Technology Data Exchange (ETDEWEB)

Meyer, Pimphan A.; Tews, Iva J.; Magnuson, Jon K.; Karagiosis, Sue A.; Jones, Susanne B.

2013-11-01

This techno-economic analysis assesses the process economics of ethanol production from lignocellulosic feedstock by fungi to identify promising opportunities, and the research needed to achieve them. Based on literature derived data, four different ethanologen strains are considered in this study: native and recombinant Saccharomyces cerevisiae, the natural pentose-fermenting yeast, Pichia stipitis and the filamentous fungus Fusarium oxysporum. In addition, filamentous fungi are applied in multi-organism and consolidated process configurations. Organism performance and technology readiness are categorized as near-term (<5 years), mid-term (5-10 years), and long-term (>10 years) process deployment. The results of the analysis suggest that the opportunity for fungal fermentation exists for lignocellulosic ethanol production.

Cofermentation of sweet sorghum juice and grain for production of fuel ethanol and distillers' wet grain

Energy Technology Data Exchange (ETDEWEB)

Gibbons, W.R.; Westby, C.A.

1989-01-01

In an attempt to reduce the costs associated with fuel ethanol production from grain, sweet sorghum juice was used as a partial or complete replacement for tap-water in mash preparation and fermentation. This juice, which was an unutilized by-product of sweet sorghum silage preservation by the Ag-Bag method, contained 6.5-7.6% (wt/wt) reducing sugar and produced up to 3.51% (v/v) ethanol beers after fermentation. Varying amounts of this juice were mixed with water and corn or wheat, either before or after liquefaction (front-end or back-end loading, respectively). When over 60% juice replacement was used in front-end loading trials, salt buildup, due to required pH adjustments during cooking, inhibited yeast metabolism and thereby reduced yields. This inhibition was not observed during back-end loading trials since acid and base usage during cooking were reduced. (author).

Ethanol production from lignocellulosic materials. Fermentation and on-line analysis

Energy Technology Data Exchange (ETDEWEB)

Olsson, L.

1994-04-01

The fermentation performance of bacteria, yeast and fungi was investigated in lignocellulosic hydrolysates with the aim of finding microorganisms which both withstand the inhibitors and that have the ability to ferment pentoses. Firstly, the performance of Saccharomyces cidri, Saccharomyces cerevisiae, Lactobacillus brevis, Lactococcus lactis ssp lactis, Escherichia coli and Zymomonas mobilis was investigated in spent sulphite liquor and enzymatic hydrolysate of steam-pretreated willow. Secondly, the performance of natural and recombinant E. coli, Pichia stipitis, recombinant S. cerevisiae, S. cerevisiae in combination with xylose isomerase and Fusarium oxysporum was investigated in a xylose-rich acid hydrolysate of corn cob. Recombinant E. coli was the best alternative for fermentation of lignocellulosic hydrolysates, giving both high yields and productivities. The main drawback was that detoxification was necessary. The kinetics of the fermentation with recombinant E. coli KO11 was investigated in the condensate of steam-pretreated willow. A cost analysis of the ethanol production from willow was made, which predicted an ethanol production cost of 3.9 SEK/l for the pentose fermentation. The detoxification cost constituted 22% of this cost. The monitoring of three monosaccharides and ethanol in lignocellulosic hydro lysates is described. The monosaccharides were determined using immobilized pyranose oxidase in an on-line amperometric analyser. Immobilization and characterization of pyranose oxidase from Phanerochaete chrysosporium is also described. The ethanol was monitored on-line using a micro dialysis probe as an in situ sampling device. The dialysate components were then separated in a column liquid chromatographic system and the ethanol was selectively detected by an amperometric alcohol bio sensor. The determinations with on-line analysis methods agreed well with off-line methods. 248 refs, 4 figs, 12 tabs

Implications of increased ethanol production

International Nuclear Information System (INIS)

1992-06-01

The implications of increased ethanol production in Canada, assuming a 10% market penetration of a 10% ethanol/gasoline blend, are evaluated. Issues considered in the analysis include the provision of new markets for agricultural products, environmental sustainability, energy security, contribution to global warming, potential government cost (subsidies), alternative options to ethanol, energy efficiency, impacts on soil and water of ethanol crop production, and acceptance by fuel marketers. An economic analysis confirms that ethanol production from a stand-alone plant is not economic at current energy values. However, integration of ethanol production with a feedlot lowers the break-even price of ethanol by about 35 cents/l, and even further reductions could be achieved as technology to utilize lignocellulosic feedstock is commercialized. Ethanol production could have a positive impact on farm income, increasing cash receipts to grain farmers up to $53 million. The environmental impact of ethanol production from grain would be similar to that from crop production in general. Some concerns about ethanol/gasoline blends from the fuel industry have been reduced as those blends are now becoming recommended in some automotive warranties. However, the concerns of the larger fuel distributors are a serious constraint on an expansion of ethanol use. The economics of ethanol use could be improved by extending the federal excise tax exemption now available for pure alcohol fuels to the alcohol portion of alcohol/gasoline blends. 9 refs., 10 tabs

Co-production of bio-ethanol, electricity and heat from biomass residues

Energy Technology Data Exchange (ETDEWEB)

Reith, J.H.; Den Uil, H.; Van Veen, H. [ECN Biomass, Petten (Netherlands); De Laat, W.T.A.M.; Niessen, J.J. [Royal Nedalco, Bergen op Zoom (Netherlands); De Jong, E.; Elbersen, H.W.; Weusthuis, R. [Agrotechnological Research Institute ATO, BU Renewable Resources, Wageningen (Netherlands); Van Dijken, J.P.; Raamsdonk, L. [Delft University of Technology, Delft (Netherlands)

2002-07-01

sections), necessitates concentration of the sugar solutions by evaporation to obtain an industrially acceptable final ethanol concentration in the fermentation broth. Follow-up RandD will focus on reduction of water use, internal water recycling and energy integration of the evaporation step with the ethanol purification section. The estimated production costs of bio-ethanol from 3 types of (ligno)cellulo sic residues are 0.75-0.99 e/l (34-45 E/GJ), which is considerably higher than the current costs of fuel ethanol from corn starch (0.34 e/l; 16.2 e/GJ) and gasoline (7.3 e/GJ). A sensitivity analysis shows that cellulase costs will have to be reduced with at least a factor 10 and capital costs need to be reduced by 30% to reach ethanol production costs competitive with ethanol from starch crops.

Private sector embedded water risk: Merging the corn supply chain network and regional watershed depletion

Science.gov (United States)

Kim, T.; Brauman, K. A.; Schmitt, J.; Goodkind, A. L.; Smith, T. M.

2016-12-01

Water scarcity in US corn farming regions is a significant risk consideration for the ethanol and meat production sectors, which comprise 80% of all US corn demand. Water supply risk can lead to effects across the supply chain, affecting annual corn yields. The purpose of our study is to assess the water risk to the US's most corn-intensive sectors and companies by linking watershed depletion estimates with corn production, linked to downstream companies through a corn transport model. We use a water depletion index as an improved metric for seasonal water scarcity and a corn sourcing supply chain model based on economic cost minimization. Water depletion was calculated as the fraction of renewable (ground and surface) water consumption, with estimates of more than 75% depletion on an annual average basis indicating a significant water risk. We estimated company water risk as the amount of embedded corn coming from three categories of water stressed counties. The ethanol sector had 3.1% of sourced corn grown from counties that were more than 75% depleted while the beef sector had 14.0%. From a firm perspective, Tyson, JBS, Cargill, the top three US corn demanding companies, had 4.5%, 9.6%, 12.8% of their sourced corn respectively, coming from watersheds that are more than 75% depleted. These numbers are significantly higher than the global average of 2.2% of watersheds being classified as more than 75% depleted. Our model enables corn using industries to evaluate their supply chain risk of water scarcity through modeling corn sourcing and watershed depletion, providing the private sector a new method for risk estimation. Our results suggest corn dependent industries are already linked to water scarcity risk in disproportionate amounts due to the spatial heterogeneity of corn sourcing and water scarcity.

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

Science.gov (United States)

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.

Simple and enhanced production of lignocellulosic ethanol by ...

African Journals Online (AJOL)

Ethanol can be produced from a fermentation process using raw materials obtained from highly economically important plants such as corn, cassava and sugarcane, and used as an alternative energy source. These economical plants are being used less because their initial cost is still increasing. However, lignocellulosic ...

Enhanced ethanol production from brewer's spent grain by a Fusarium oxysporum consolidated system

Directory of Open Access Journals (Sweden)

Christakopoulos Paul

2009-02-01

Full Text Available Abstract Background Brewer's spent grain (BG, a by-product of the brewing process, is attracting increasing scientific interest as a low-cost feedstock for many biotechnological applications. BG in the present study is evaluated as a substrate for lignocellulolytic enzyme production and for the production of ethanol by the mesophilic fungus Fusarium oxysporum under submerged conditions, implementing a consolidated bioconversion process. Fermentation experiments were performed with sugar mixtures simulating the carbohydrate content of BG in order to determine the utilization pattern that could be expected during the fermentation of the cellulose and hemicellulose hydrolysate of BG. The sugar mixture fermentation study focused on the effect of the initial total sugar concentration and on the effect of the aeration rate on fermenting performance of F. oxysporum. The alkali pretreatment of BG and different aeration levels during the ethanol production stage were studied for the optimization of the ethanol production by F. oxysporum. Results Enzyme yields as high as 550, 22.5, 6.5, 3225, 0.3, 1.25 and 3 U per g of carbon source of endoglucanase, cellobiohydrolase, β-D-glucosidase, xylanase, feruloyl esterase, β-D-xylosidase and α-L-arabinofuranosidase respectively, were obtained during the growth stage under optimized submerged conditions. An ethanol yield of 109 g ethanol per kg of dry BG was obtained with alkali-pretreated BG under microaerobic conditions (0.01 vvm, corresponding to 60% of the theoretical yield based on total glucose and xylose content of BG. Conclusion The enzymatic profile of the extracellular extract from F. oxysporum submerged cultures using BG and corn cob as the carbon source was proved efficient for a successful hydrolysis of BG. The fermentation study carried out using sugar mixtures simulating BG's carbohydrates content and consecutively alkali-pretreated and untreated BG, indicates that BG hydrolysis is the bottleneck

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

Science.gov (United States)

West, T P; Strohfus, B

1996-01-01

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

A Comparative Assessment of the Broiler:Corn Ratio and Its Impact on Broiler Processors' Profitability

OpenAIRE

Hamm, Sandra J.; Goodwin, Harold L., Jr.; McKenzie, Andrew M.

2008-01-01

Input prices for broiler production, particularly corn, are becoming increasingly volatile due to increasing competition for corn from ethanol and biofuels production suggesting volatility in poultry profits will follow indicator of profits relating feed input prices and broiler meat output prices, such as a Broiler:corn ratios. Total chicken exports, total chicken ready-to-cook production, number of eggs set, number of chicks placed, and cold storage chicken inventory are used to estimate. U...

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

Energy Technology Data Exchange (ETDEWEB)

Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); Qin, Zhangcai [Argonne National Lab. (ANL), Argonne, IL (United States); Mueller, Steffen [Univ. of Illinois at Chicago, Chicago, IL (United States); Kwon, Ho-young [International Food Policy Research Institute (IFPRI), Washington, DC (United States); Wander, Michelle M. [Univ. of Illinois, Urbana-Champaign, IL (United States); Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States)

2014-09-01

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

Ethanol as an Alternative Fuel for Automobiles: Using the First Law of Thermodynamics to Calculate the "Corn-Area-per-Car" Ratio

Science.gov (United States)

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…

Do energy prices stimulate food price volatility? Examining volatility transmission between US oil, ethanol and corn markets

NARCIS (Netherlands)

Gardebroek, C.; Hernandez, M.A.

2013-01-01

This paper examines volatility transmission in oil, ethanol and corn prices in the United States between 1997 and 2011. We follow a multivariate GARCH approach to evaluate the level of interdependence and the dynamics of volatility across these markets. Preliminary results indicate a higher

Do energy prices stimulate food price volatility? Examining volatility transmission between US oil, ethanol and corn markets

NARCIS (Netherlands)

Gardebroek, C.; Hernandez, M.A.

2012-01-01

This paper examines volatility transmission in oil, ethanol and corn prices in the United States between 1997 and 2011. We follow a multivariate GARCH approach to evaluate the level of interdependence and the dynamics of volatility across these markets. Preliminary results indicate a higher

Do energy prices stimulate food price volatility? Examining volatility transmission between US oil, ethanol and corn markets

NARCIS (Netherlands)

Hernandez, M.A.; Gardebroek, C.

2012-01-01

This paper examines volatility transmission in oil, ethanol and corn prices in the United States between 1997 and 2011. We follow a multivariate GARCH approach to evaluate the level of interdependence and the dynamics of volatility across these markets. The estimation results indicate a higher

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

Science.gov (United States)

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

Ethanol fuel gets the hangover

International Nuclear Information System (INIS)

Anon.

2007-01-01

Corn, wheat, sugar cane.. The multiplication of biofuel refineries has led to a rise of the prices of agriculture products. The question is: do we need ethanol? The US situation gives an answer: the offer exceeds the demand and ethanol prices have dropped down. Other environmental and socio-economical consequences of biofuels development are put forward by the UNO, the IMF and by non-governmental organizations who foresee a dramatic rise of food products prices and an aggravation of starvation in developing countries. (J.S.)

Ecosystem and human health impacts from increased corn production: vulnerability assessment of exposure to high nitrate concentrations in groundwater and blue baby syndrome

Science.gov (United States)

Garcia, V.; Cooter, E. J.

2013-12-01

The Renewable Fuel Standard (RFS) requires oil refiners to reach a target of 15 billion gallons of corn-based ethanol by 2022. However, there are concerns that the broad-scale use of corn as a source of ethanol may lead to unintended economic and environmental consequences. This study applies the geophysical relationships captured with linked meteorological, air quality and agriculture models to examine the impact of corn production before enactment of the RFS in 2002 and at the height of the RFS targets in 2022. In particular, we investigate the probability of high-levels of nitrate in groundwater resulting from increased corn production and then relate this vulnerability to the potential for infants to acquire Methemoglobinemia, or 'Blue Baby Syndrome'. Blue Baby Syndrome (BBS) is a potentially fatal condition that occurs when the hemoglobin (Fe2+) in an infant's red blood cells is oxidized to methemoglobin (Fe3+), preventing the uptake of oxygen from the baby's blood. Exposure to high levels of nitrate in groundwater occur near the intersection of areas where surface water can more readily leach into shallow aquifers, wells are the main source of drinking water, and high nitrogen inputs exist. We use a coupled meteorological, agricultural and air quality model to identify areas vulnerable to increased nitrate contamination and associated risk to acquiring BBS. We first verify the relationship between predictive variables (e.g., nitrogen deposition and fertilization rates, landcover, soils and aquifer type) and nitrate groundwater levels by applying a regression model to over 800 nitrate measurements taken from wells located throughout the US (Figure 1). We then apply the regression coefficients to the coupled model output to identify areas that are at an increased risk for high nitrate groundwater levels in 2022. Finally, we examine the potential change in risk for acquiring BBS resulting from increased corn production by applying an Oral Reference Dose (Rf

Oxidative production of xylonic acid using xylose in distillation stillage of cellulosic ethanol fermentation broth by Gluconobacter oxydans.

Science.gov (United States)

Zhang, Hongsen; Han, Xushen; Wei, Chengxiang; Bao, Jie

2017-01-01

An oxidative production process of xylonic acid using xylose in distillation stillage of cellulosic ethanol fermentation broth was designed, experimentally investigated, and evaluated. Dry dilute acid pretreated and biodetoxified corn stover was simultaneously saccharified and fermented into 59.80g/L of ethanol (no xylose utilization). 65.39g/L of xylose was obtained in the distillation stillage without any concentrating step after ethanol was distillated. Then the xylose was completely converted into 66.42g/L of xylonic acid by Gluconobacter oxydans. The rigorous Aspen Plus modeling shows that the wastewater generation and energy consumption was significantly reduced comparing to the previous xylonic acid production process using xylose in pretreatment liquid. This study provided a practical process option for xylonic acid production from lignocellulose feedstock with significant reduction of wastewater and energy consumption. Copyright © 2016 Elsevier Ltd. All rights reserved.

Corn Production. A Unit for Teachers of Vocational Agriculture. Production Agriculture Curriculum Materials Project.

Science.gov (United States)

Grace, Clyde, Jr.

Designed to provide instructional materials for use by vocational agriculture teachers, this unit contains nine lessons based upon competencies needed to maximize profits in corn production. The lessons cover opportunities for growing corn; seed selection; seedbed preparation; planting methods and practices; fertilizer rates and application;…

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

Energy Technology Data Exchange (ETDEWEB)

Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Qin, Zhangcai [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Mueller, Steffen [Univ. of Illinois, Chicago, IL (United States). Energy Resources Center; Kwon, Ho-young [International Food Policy Research Institute (IFPRI), Washington, DC (United States); Wander, Michelle M. [Univ. of Illinois at Urbana Champaign, Urbana, IL (United States). Dept. of Natural Resources; Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division

2016-09-01

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

Forecasting corn production in Serbia using ARIMA model

Directory of Open Access Journals (Sweden)

Ilić Ivana

2016-01-01

Full Text Available Agricultural crop production is closely related to climate, as a decisive success factor. Temperature fluctuations and changes in the volume of precipitation are the main factors affecting the growth and development of crops, and, ultimately, the quantity produced. Corn is the most common crop necessary to provide for domestic needs, and a strategic product for export. Production of corn in the period from 1947 to 2014 in Serbia had an oscillatory trend, with significant jumps and falls in production. The subject of this paper is the forecasting of future trends in corn production in Serbia. Building on the subject, the purpose of this paper is to create the model for forecasting future corn production and establishing its trends.

Ethanol production

Energy Technology Data Exchange (ETDEWEB)

Kolleurp, F; Daugulis, A J

1985-05-01

Extractive fermentation is a technique that can be used to reduce the effect of end-product inhibition through the use of a water-immiscible phase which removes fermentation products in situ. This has the beneficial effect of not only removing inhibitory products as they are formed (thus keeping reaction rates high) but also has the potential for reducing product recovery costs. We have chosen to examine the ethanol fermentation as a model system for end product inhibition and extractive fermentation, and have developed a computer model predicting the productivity enhancement possible with this technique. The model predicts an ethanol productivity of 82.6 g/L-h if a glucose feed of 750 g/L is fermented with a solvent having a distribution coefficient of 0.5 at a dilution rate of 5.0 h . This is more than 10 times higher than for a conventional chemostat fermentation of a 250 g/L glucose feed. In light of this, a systematic approach to extractive fermentation has been undertaken involving the screening of more than 1,000 solvents for their extractive properties. UNIFAC and UNIQUAC estimates of distribution coefficients and selectivities were compiled and ranked in a database, together with other important physical properties, such as density, surface tension and viscosity. Preliminary shake-flask and chemostat biocompatibility studies on the most promising solvents have been undertaken. The previous predictive, data base and experimental results are discussed.

Assessment of soil attributes and crop productivity after diversification of the ubiquitous corn-soybean rotation in the northwestern U.S. Corn Belt

Science.gov (United States)

Highly specialized cash-grain production systems based upon corn-soybean rotations under tilled soil management are common in the northwestern U.S. Corn Belt. This study, initiated in 1997, was conducted to determine if diversification of this ubiquitous corn-soybean rotation would affect soil char...

Crop Management Effects on the Energy and Carbon Balances of Maize Stover-Based Ethanol Production

Directory of Open Access Journals (Sweden)

Prem Woli

2014-12-01

Full Text Available This study was conducted to identify the crop management options—the combinations of various cultivars, irrigation amounts, planting dates, and soils—that would maximize the energy sustainability and eco-friendliness of maize (Zea mays L. stover-based ethanol production systems in the Mississippi Delta. Stover yields simulated with CERES-Maize were used to compute net energy value (NEV and carbon credit balance (CCB, the indicators of sustainability and eco-friendliness of ethanol production, respectively, for various scenarios. As the results showed, deeper soils with higher water holding capacities had larger NEV and CCB values. Both NEV and CCB had sigmoid relationships with irrigation amount and planting date and could be maximized by planting the crop during the optimum planting window. Stover yield had positive effects on NEV and CCB, whereas travel distance had negative. The influence of stover yield was larger than that of travel distance, indicating that increasing feedstock yields should be emphasized over reducing travel distance. The NEV and CCB values indicated that stover-based ethanol production in the Mississippi Delta is sustainable and environmentally friendly. The study demonstrated that the energy sustainability and eco-friendliness of maize stover-based ethanol production could be increased with alternative crop management options.

Ethanol is a strategic raw material

Directory of Open Access Journals (Sweden)

Baras Josip K.

2002-01-01

Full Text Available The first part of this review article considers general data about ethanol as an industrial product, its qualities and uses. It is emphasized that, if produced from biomass as a renewable raw material, its perspectives as a chemical raw material and energent are brilliant. Starchy grains, such as corn, must be used as the main raw materials for ethanol production. The production of bioethanol by the enzyme-catalyzed conversion of starch followed by (yeast fermentation, distillation is the process of choice. If used as a motor fuel, anhydrous ethanol can be directly blended with gasoline or converted into an oxygenator such as ETBE. Finally, bioethanol production in Yugoslavia and the possibilities for its further development are discussed.

Biomass production and composition of temperate and tropical maize in central Iowa

Science.gov (United States)

Bioethanol production in the Midwestern U.S. has largely focused on corn (Zea mays L.) grain for starch-based ethanol production. There has been growing interest in lignocellulosic biomass as a feedstock for biofuels. Because corn adapted to the tropics does not initiate senescence as early as ada...

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

Science.gov (United States)

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

Enhancement of enzymatic hydrolysis of corn stover by γ-irradiation and combined solvent delignification/acid prehydrolysis

International Nuclear Information System (INIS)

Nghiem, N.P.; Gonzales-Valdes, A.; Moo-Young, M.; Robinson, C.W.

1984-01-01

Two pretreatment schemes were studied for their effect on the enhancement of soluble sugar production from corn stover by enzymatic hydrolysis. In the first scheme, prior to enzymic hydrolysis corn stover which was ground to pass a 1 mm screen was immersed in NaOH solution and exposed to gamma irradiation. The NaOH levels and radiation dosages were varied from 0 to 0.51 gNaOH/g corn stover and from 50 to 150 Mr, respectively. The combined residue and solubles were then hydrolyzed with a commercial cellulase (Onozuka) in 0.05 M citrate buffer at pH 4.6 and 39 0 C for 48 hours. The highest sugar yield of 96% based on the total carbohydrate content of the original sample was obtained at 100 Mr and 0.06 gNaOH/g corn stover. In the second scheme, corn stover which was ground to pass a 0.35 mm screen was delignified with ethanol-water-NaOH. The ethanol-water mixture used contained 3 parts (by volume) of 95% ethanol and 4 g NaOH/L; substrate concentration was 5% (w/v). The delignification was carried out at 140 0 C for 1 hour. At these conditions, 65% of the lignin was removed while 90% of the carbohydrates remained insoluble. The delignified corn stover with an without treatment using 2% wt.% H 2 SO 4 at 95 0 C and 1 hour was then enzymically hydrolyzed with Novo Cellulclast at pH 4.8 and 50 0 C for up to 48 hours. Factors that affect the overall sugar production are presented and discussed. In addition, the overall sugar yields for the two schemes are compared with other pretreatment schemes reported. (orig.)

Rescuing ethanol photosynthetic production of cyanobacteria in non-sterilized outdoor cultivations with a bicarbonate-based pH-rising strategy.

Science.gov (United States)

Zhu, Zhi; Luan, Guodong; Tan, Xiaoming; Zhang, Haocui; Lu, Xuefeng

2017-01-01

Ethanol photosynthetic production based on cyanobacteria cell factories utilizing CO 2 and solar energy provides an attractive solution for sustainable production of green fuels. However, the scaling up processes of cyanobacteria cell factories were usually threatened or even devastated by biocontaminations, which restricted biomass or products accumulations of cyanobacteria cells. Thus it is of great significance to develop reliable biocontamination-controlling strategies for promoting ethanol photosynthetic production in large scales. The scaling up process of a previously developed Synechocystis strain Syn-HZ24 for ethanol synthesis was severely inhibited and devastated by a specific contaminant, Pannonibacter phragmitetus , which overcame the growths of cyanobacteria cells and completely consumed the ethanol accumulation in the cultivation systems. Physiological analysis revealed that growths and ethanol-consuming activities of the contaminant were sensitive to alkaline conditions, while ethanol-synthesizing cyanobacteria strain Syn-HZ24 could tolerate alkaline pH conditions as high as 11.0, indicating that pH-increasing strategy might be a feasible approach for rescuing ethanol photosynthetic production in outdoor cultivation systems. Thus, we designed and evaluated a Bicarbonate-based Integrated Carbon Capture System (BICCS) derived pH-rising strategy to rescue the ethanol photosynthetic production in non-sterilized conditions. In lab scale artificially simulated systems, pH values of BG11 culture medium were maintained around 11.0 by 180 mM NaHCO 3 and air steam, under which the infection of Pannonibacter phragmitetus was significantly restricted, recovering ethanol production of Syn-HZ24 by about 80%. As for outdoor cultivations, ethanol photosynthetic production of Syn-HZ24 was also successfully rescued by the BICCS-derived pH-rising strategy, obtaining a final ethanol concentration of 0.9 g/L after 10 days cultivation. In this work, a novel product

Integrated Biorefineries with Engineered Microbes and High-value Co-products for Profitable Biofuels Production

Science.gov (United States)

Corn-based fuel ethanol production processes provide several advantages which could be synergistically applied to overcome limitations of biofuel processes based on lignocellulose. These include resources such as equipment, manpower, nutrients, water, and heat. The fact that several demonstration-...

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

Science.gov (United States)

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.

Investigation of potential of agro-industrial residues for ethanol production by using Candida tropicalis and Zymomonas mobilis

Science.gov (United States)

Patle, Sonali

India is becoming more susceptible regarding energy security with increasing world prices of crude oil and increasing dependence on imports. Based on experiments by the Indian Institute of Petroleum, a 10% ethanol blend with gasoline is being considered for use in vehicles in at least one state and it will be mandatory for all oil companies to blend petrol with 10% ethanol from October 2008. In view of the above, the Government has already started supply of 5% ethanol blended petrol from 2003 in nine states and four contiguous Union Territories. Currently, fuel ethanol is produced mainly from molasses, corn, wheat and sugar beets. The production cost of ethanol from these agro-feedstocks is more than twice the price of gasoline. The high feedstock cost poses a major obstacle to large scale implementation of ethanol as a transportation fuel. Molasses could be in short supply due to the implementation of 10% blending norm. A reduction in import duty for industrial alcohol from7.5% to 5% has been suggested. The use of lignocellulosic energy crops, and particularly low cost biomass residues, offers excellent perspectives for application of ethanol in transportation fuels (Ridder, 2000). These materials will increase the ethanol production capacity and reduce the production cost to a competitive level. There is a huge demand (500 million litres) of ethanol to meet the 5% blending in India. With the present infrastructure, only 90 million litres of ethanol was produced till November 2006 and could reach up to 140 million litres (around) till October 2007. Bioethanol from these materials provides a highly cost effective option for CO2 emission reduction in the transportation sector. The aim of the present investigation was to evaluate the potential of biomass as feedstock for ethanol production. The dedicated energy crops would require thorough support as well as planning efforts such as assessing resources, availability and utilization. Furthermore, applied research is

Ethanol Basics

Energy Technology Data Exchange (ETDEWEB)

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.

Abatement cost of GHG emissions for wood-based electricity and ethanol at production and consumption levels.

Directory of Open Access Journals (Sweden)

Puneet Dwivedi

Full Text Available 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.

Sorghum to Ethanol Research

Energy Technology Data Exchange (ETDEWEB)

Dahlberg, Jeffrey A. [Univ. of California, Parlier, CA (United States). Kearney Research and Extension Center; Wolfrum, Edward J. [National Renewable Energy Lab. (NREL), Golden, CO (United States). Process and Analytical Engineering Group

2010-09-28

The development of a robust source of renewable transportation fuel will require a large amount of biomass feedstocks. It is generally accepted that in addition to agricultural and forestry residues, we will need crops grown specifically for subsequent conversion into fuels. There has been a lot of research on several of these so-called "dedicated bioenergy crops" including switchgrass, miscanthus, sugarcane, and poplar. It is likely that all of these crops will end up playing a role as feedstocks, depending on local environmental and market conditions. Many different types of sorghum have been grown to produce syrup, grain, and animal feed for many years. It has several features that may make it as compelling as other crops mentioned above as a renewable, sustainable biomass feedstock; however, very little work has been done to investigate sorghum as a dedicated bioenergy crop. The goal of this project was to investigate the feasibility of using sorghum biomass to produce ethanol. The work performed included a detailed examination of the agronomics and composition of a large number of sorghum varieties, laboratory experiments to convert sorghum to ethanol, and economic and life-cycle analyses of the sorghum-to-ethanol process. This work showed that sorghum has a very wide range of composition, which depended on the specific sorghum cultivar as well as the growing conditions. The results of laboratory- and pilot-scale experiments indicated that a typical high-biomass sorghum variety performed very similarly to corn stover during the multi-step process required to convert biomass feedstocks to ethanol; yields of ethanol for sorghum were very similar to the corn stover used as a control in these experiments. Based on multi-year agronomic data and theoretical ethanol production, sorghum can achieve more than 1,300 gallons of ethanol per acre given the correct genetics and environment. In summary, sorghum may be a compelling dedicated bioenergy crop that could help

Environmental implications of accelerated gasohol production: preliminary assessment

Energy Technology Data Exchange (ETDEWEB)

1980-01-01

This report assesses the environmental impacts of increasing US production of fuel ethanol by 330 million gallons per year in the 1980 to 1981 time frame in order to substitute gasohol for 10% of the unleaded gasoline consumed in the United States. Alternate biomass feedstocks are examined and corn is selected as the most logical feedstock, based on its availability and cost. Three corn conversion processes that could be used to attain the desired 1980 to 1981 production are identified; fermentation plants that use a feedstock of starch and wastes from an adjacent corn refining plants are found to have environmental and economic advantages. No insurmountable environmental problems can be achieved using current technology; the capital and operating costs of this control are estimated. If ethanol production is increased substantially after 1981, the environmentally acceptable use or disposal of stillage, a liquid by-product of fermentation, could become a serious problem.

A generalized disjunctive programming framework for the optimal synthesis and analysis of processes for ethanol production from corn stover.

Science.gov (United States)

Scott, Felipe; Aroca, Germán; Caballero, José Antonio; Conejeros, Raúl

2017-07-01

The aim of this study is to analyze the techno-economic performance of process configurations for ethanol production involving solid-liquid separators and reactors in the saccharification and fermentation stage, a family of process configurations where few alternatives have been proposed. Since including these process alternatives creates a large number of possible process configurations, a framework for process synthesis and optimization is proposed. This approach is supported on kinetic models fed with experimental data and a plant-wide techno-economic model. Among 150 process configurations, 40 show an improved MESP compared to a well-documented base case (BC), almost all include solid separators and some show energy retrieved in products 32% higher compared to the BC. Moreover, 16 of them also show a lower capital investment per unit of ethanol produced per year. Several of the process configurations found in this work have not been reported in the literature. Copyright © 2017 Elsevier Ltd. All rights reserved.

An evaluation of cassava, sweet potato and field corn as potential carbohydrate sources for bioethanol production in Alabama and Maryland

Energy Technology Data Exchange (ETDEWEB)

Ziska, Lewis H.; Tomecek, Martha; Sicher, Richard [United States Department of Agriculture, Agricultural Research Service, Crop Systems and Global Change Lab, 10300 Baltimore Avenue, Building 1, Beltsville, MD 20705 (United States); Runion, G. Brett; Prior, Stephen A.; Torbet, H. Allen [United States Department of Agriculture, Agricultural Research Service, National Soil Dynamics Laboratory, 411 South Donahue Drive, Auburn, AL 36832 (United States)

2009-11-15

The recent emphasis on corn production to meet the increasing demand for bioethanol has resulted in trepidation regarding the sustainability of the global food supply. To assess the potential of alternative crops as sources of bioethanol production, we grew sweet potato (Ipomoea batatas) and cassava (Manihot esculentum) at locations near Auburn, Alabama and Beltsville, Maryland in order to measure root carbohydrate (starch, sucrose, glucose) and root biomass. Averaged for both locations, sweet potato yielded the highest concentration of root carbohydrate (ca 80%), primarily in the form of starch (ca 50%) and sucrose (ca 30%); whereas cassava had root carbohydrate concentrations of (ca 55%), almost entirely as starch. For sweet potato, overall carbohydrate production was 9.4 and 12.7 Mg ha{sup -1} for the Alabama and Maryland sites, respectively. For cassava, carbohydrate production in Maryland was poor, yielding only 2.9 Mg ha{sup -1}. However, in Alabama, carbohydrate production from cassava averaged {proportional_to}10 Mg ha{sup -1}. Relative to carbohydrate production from corn in each location, sweet potato and cassava yielded approximately 1.5 x and 1.6 x as much carbohydrate as corn in Alabama; 2.3 x and 0.5 x for the Maryland site. If economical harvesting and processing techniques could be developed, these data suggest that sweet potato in Maryland, and sweet potato and cassava in Alabama, have greater potential as ethanol sources than existing corn systems, and as such, could be used to replace or offset corn as a source of biofuels. (author)

Re-engineering bacteria for ethanol production

Science.gov (United States)

Yomano, Lorraine P; York, Sean W; Zhou, Shengde; Shanmugam, Keelnatham; Ingram, Lonnie O

2014-05-06

The invention provides recombinant bacteria, which comprise a full complement of heterologous ethanol production genes. Expression of the full complement of heterologous ethanol production genes causes the recombinant bacteria to produce ethanol as the primary fermentation product when grown in mineral salts medium, without the addition of complex nutrients. Methods for producing the recombinant bacteria and methods for producing ethanol using the recombinant bacteria are also disclosed.

Sorghum to Ethanol Research Initiative: Cooperative Research and Development Final Report, CRADA Number CRD-08-291

Energy Technology Data Exchange (ETDEWEB)

Wolfrum, E.

2011-10-01

The goal of this project was to investigate the feasibility of using sorghum to produce ethanol. The work performed included a detailed examination of the agronomics and composition of a large number of sorghum varieties, laboratory experiments to convert sorghum to ethanol, and economic and life-cycle analyses of the sorghum-to-ethanol process. This work showed that sorghum has a very wide range of composition, which depended on the specific sorghum cultivar as well as the growing conditions. The results of laboratory- and pilot-scale experiments indicated that a typical high-biomass sorghum variety performed very similarly to corn stover during the multi-step process required to convert biomass feedstocks to ethanol; yields of ethanol for sorghum were very similar to the corn stover used as a control in these experiments. Based on multi-year agronomic data and theoretical ethanol production, sorghum can achieve more than 1,300 gallons of ethanol per acre given the correct genetics and environment. In summary, sorghum may be a compelling dedicated bioenergy crop that could help provide a portion of the feedstocks required to produce renewable domestic transportation fuels.

Establishing an ethanol production business

International Nuclear Information System (INIS)

1993-01-01

Many Saskatchewan communities are interested in the potential benefits of establishing an ethanol production facility. A guide is presented to outline areas that communities should consider when contemplating the development of an ethanol production facility. Political issues affecting the ethanol industry are discussed including environmental impacts, United States legislation, Canadian legislation, and government incentives. Key success factors in starting a business, project management, marketing, financing, production, physical requirements, and licensing and regulation are considered. Factors which must be taken into consideration by the project manager and team include markets for ethanol and co-products, competent business management staff, equity partners for financing, production and co-product utilization technologies, integration with another facility such as a feedlot or gluten plant, use of outside consultants, and feedstock, water, energy, labour, environmental and site size requirements. 2 figs., 2 tabs

Modifying Yeast Tolerance to Inhibitory Conditions of Ethanol Production Processes

DEFF Research Database (Denmark)

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....

Processing cereal grains, thin stillage, and cheese whey to fuel ethanol in a farm-scale plant

Energy Technology Data Exchange (ETDEWEB)

Gibbons, W R; Westby, C A

1988-01-01

Hydrous fuel ethanol (95%) and distiller's wet grain (DWG) were produced in a farm-scale plant from corn, wheat, and grain sorghum particles of various sizes, from corn combined with thin stillage-whey, and from various other cereal grains. These variations were made in a search to find the best set of conditions for maximizing the energy balance and minimizing the cost of ethanol production. We found that the optimum hammermill screen size for corn, wheat, and grain sorghum was 1.59 - 2.38 mm. In tests with thin stillage and whey a higher energy balance (2.91) occurred when one part whey was mixed with three parts stillage, rather than the reverse (2.69). However, the reverse (three parts whey and one part stillage) gave a lower ethanol cost ($0.45 liter/sup -1/) than the original ($0.47 liter/sup -1/). Tests with various cereal grains (corn, oats, wheat, barley, rye, and grain sorghum) gave identical energy balance values (2.26) when 10% (v/v) ethanol beers were produced. However, rye ($0.50 liter/sup -1/), grain sorghum ($0.46 liter/sup -1/), and corn ($0.51 liter/sup -1/) yielded ethanol at the lowest net cost. Recommendations for farm-scale plants are also provided.

Analysis of the Efficiency of the U.S. Ethanol Industry 2007

Energy Technology Data Exchange (ETDEWEB)

Wu, May [Argonne National Lab. (ANL), Argonne, IL (United States)

2008-03-27

In 2007, the Renewable Fuels Association (RFA) conducted a survey of US ethanol production plants to provide an assessment of the current US ethanol industry. The survey covers plant operations in both corn dry mills and wet mills. In particular, it includes plant type, ownership structure, capacity, feedstocks, production volumes, coproducts, process fuel and electricity usage, water consumption, and products transportation and distribution. This report includes a summary and analysis of these results.

Use of corn distiller's solubles from an ethanol plant for aquaculture

Energy Technology Data Exchange (ETDEWEB)

Kohler, C.C.

1984-06-01

Wet stillage can economically be separated into two fractions: distiller's grain and distiller's solubles. Wet corn distiller's grain has shown potential as a feed supplement for ruminants, swine, and poultry. However, the soluble fraction (with suspended particles) is of little food value to terrestrial animals because of its high water content; it is not generally economically feasible to concentrate it further. The purpose of this project is to determine if the soluble by-product could potentially be used as a food source in an aquatic environment where its high water content would not necessarily pose an impediment. Studies have shown that corn distiller's solubles are not highly toxic to aquatic organisms at concentrations ranging up to 10,000 ppM. However, the high biological oxygen demand of the material requires that it be administered to ponds at rates less than 2000 ppM on a daily basis. Golden shiners were observed to actively consume the particulates of the corn distiller's solubles. Direct consumption of the particulates by fish makes the use of corn distiller's solubles in aquaculture much more attractive than if the by-product only serves to increase pond fertility. Despite the minimum amount of food material added to the ponds, production of shrimp and fish was favorable over the 4 month growing periods. Golden shiners reared in the same ponds as shrimp had production rates equivalent to 130 kg ha/sup -1/. Monoculture of shrimp at higher densities (3000 to 5000 shrimp stocked per pond versus 2000 in 1982) resulted in an average production equivalent to approximately 228 kg ha/sup -1/, with individual shrimp averaging 10.5 g. Based on estimated wholesale prices of $10.00 and $7.75 per kilogram for frozen shrimp and live fish, respectively, the gross profit margin would have exceeded $2000 ha/sup -1/ both years. 25 references, 13 figures, 13 tables.

Ethanol production from cellulose, lactose and xylose using yeasts and enzymes. Gewinnung von Ethanol aus Cellulose, Lactose, und Xylose mit Hilfe von Hefen und Enzymen

Energy Technology Data Exchange (ETDEWEB)

Schwank, U

1986-07-03

Experiments with mixtures of whey and corn showed that more than 85% of the lactose was degraded into ethanol. The applicability of cellulose was investigated by means of potatoes. Cellulase is inhibited by glucose, which is a fermentation intermediate, as well as by the end product ethanol. A cellulase inhibitor in potatoes was detected and stabilized; this inhibitor could be degraded into neutral components by a suitable enzyme. Saccharification and fermentation experiments showed that the cellulose fraction of potatoes can be reduced efficiently. The effects of non-enzymatic pretreatment on enzymatic degradation of cellulose, combined with fermentation of the degradation products, are illustrated by the example of cellulose treated with acid and alkaline substances. A continuous fermentation system was developed from which the ethanol is withdrawn in vapour form. The system made better use of the cellulase activity and increased the efficiency of a xylose-fermenting yeast. The new method is compared with batch experiments in order to assess its efficiency. The advantages of the continuous process are proved for two yeasts of the species Pachysolu and Pichia. Specific fermentation rates up to 0.08 g/(g x h) and fermentation yields up to 0.42 g ethanol/g xylose were achieved with Pichia stipitis.

Modifying yeast tolerance to inhibitory conditions of ethanol production processes

Directory of Open Access Journals (Sweden)

Luis eCaspeta

2015-11-01

Full Text Available 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.

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

Energy Technology Data Exchange (ETDEWEB)

Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); Qin, Zhangcai [Argonne National Lab. (ANL), Argonne, IL (United States); Mueller, Steffen [Univ. of Illinois, Chicago, IL (United States); Kwon, Ho-young [International Food Policy Research Inst., Washington, DC (United States); Wander, Michelle M. [Univ. of Illinois, Urbana-Champaign, IL (United States); Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States)

2017-12-01

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

Anaerobic digestion of whole stillage from dry-grind corn ethanol plant under mesophilic and thermophilic conditions.

Science.gov (United States)

Eskicioglu, Cigdem; Kennedy, Kevin J; Marin, Juan; Strehler, Benjamin

2011-01-01

Anaerobic digestion of whole stillage from a dry-grind corn-based ethanol plant was evaluated by batch and continuous-flow digesters under thermophilic and mesophilic conditions. At whole corn stillage concentrations of 6348 to 50,786 mg total chemical oxygen demand (TCOD)/L, at standard temperature (0 °C) and pressure (1 atm), preliminary biochemical methane potential assays produced 88±8 L (49±5 L CH4) and 96±19 L (65±14 L CH4) biogas per L stillage from mesophilic and thermophilic digesters, respectively. Continuous-flow studies for the full-strength stillage (TCOD=254 g/L) at organic loadings of 4.25, 6.30 and 9.05 g TCOD/L days indicated unstable performance for the thermophilic digester. Among the sludge retention times (SRTs) of 60, 45 and 30 days tested, the mesophilic digestion was successful only at 60 days-SRT which does not represent a practical operation time for a large scale bioethanol plant. Future laboratory studies will focus on different reactor configurations to reduce the SRT needed in the digesters. Copyright © 2010 Elsevier Ltd. All rights reserved.

A framework for model-based optimization of bioprocesses under uncertainty: Lignocellulosic ethanol production case

DEFF Research Database (Denmark)

Morales Rodriguez, Ricardo; Meyer, Anne S.; Gernaey, Krist

2012-01-01

of up to 0.13 USD/gal-ethanol. Further stochastic optimization demonstrated the options for further reduction of the production costs with different processing configurations, reaching a reduction of up to 28% in the production cost in the SHCF configuration compared to the base case operation. Further...

Effect of dilute alkaline pretreatment on the conversion of different parts of corn stalk to fermentable sugars and its application in acetone-butanol-ethanol fermentation.

Science.gov (United States)

Cai, Di; Li, Ping; Luo, Zhangfeng; Qin, Peiyong; Chen, Changjing; Wang, Yong; Wang, Zheng; Tan, Tianwei

2016-07-01

To investigate the effect of dilute alkaline pretreatment on different parts of biomass, corn stalk was separated into flower, leaf, cob, husk and stem, which were treated by NaOH in range of temperature and chemical loading. The NaOH-pretreated solid was then enzymatic hydrolysis and used as the substrate for batch acetone-butanol-ethanol (ABE) fermentation. The results demonstrated the five parts of corn stalk could be used as potential feedstock separately, with vivid performances in solvents production. Under the optimized conditions towards high product titer, 7.5g/L, 7.6g/L, 9.4g/L, 7g/L and 7.6g/L of butanol was obtained in the fermentation broth of flower, leaf, cob, husk and stem hydrolysate, respectively. Under the optimized conditions towards high product yield, 143.7g/kg, 126.3g/kg, 169.1g/kg, 107.7g/kg and 116.4g/kg of ABE solvent were generated, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metabolic engineering of Saccharomyces cerevisiae ethanol strains PE-2 and CAT-1 for efficient lignocellulosic fermentation.

Science.gov (United States)

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.

The ethanol pathway from Thermoanaerobacterium saccharolyticum improves ethanol production in Clostridium thermocellum.

Science.gov (United States)

Hon, Shuen; Olson, Daniel G; Holwerda, Evert K; Lanahan, Anthony A; Murphy, Sean J L; Maloney, Marybeth I; Zheng, Tianyong; Papanek, Beth; Guss, Adam M; Lynd, Lee R

2017-07-01

Clostridium thermocellum ferments cellulose, is a promising candidate for ethanol production from cellulosic biomass, and has been the focus of studies aimed at improving ethanol yield. Thermoanaerobacterium saccharolyticum ferments hemicellulose, but not cellulose, and has been engineered to produce ethanol at high yield and titer. Recent research has led to the identification of four genes in T. saccharolyticum involved in ethanol production: adhE, nfnA, nfnB and adhA. We introduced these genes into C. thermocellum and observed significant improvements to ethanol yield, titer, and productivity. The four genes alone, however, were insufficient to achieve in C. thermocellum the ethanol yields and titers observed in engineered T. saccharolyticum strains, even when combined with gene deletions targeting hydrogen production. This suggests that other parts of T. saccharolyticum metabolism may also be necessary to reproduce the high ethanol yield and titer phenotype in C. thermocellum. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

A Production Efficiency Model-Based Method for Satellite Estimates of Corn and Soybean Yields in the Midwestern US

Directory of Open Access Journals (Sweden)

Andrew E. Suyker

2013-11-01

Full Text Available Remote sensing techniques that provide synoptic and repetitive observations over large geographic areas have become increasingly important in studying the role of agriculture in global carbon cycles. However, it is still challenging to model crop yields based on remotely sensed data due to the variation in radiation use efficiency (RUE across crop types and the effects of spatial heterogeneity. In this paper, we propose a production efficiency model-based method to estimate corn and soybean yields with MODerate Resolution Imaging Spectroradiometer (MODIS data by explicitly handling the following two issues: (1 field-measured RUE values for corn and soybean are applied to relatively pure pixels instead of the biome-wide RUE value prescribed in the MODIS vegetation productivity product (MOD17; and (2 contributions to productivity from vegetation other than crops in mixed pixels are deducted at the level of MODIS resolution. Our estimated yields statistically correlate with the national survey data for rainfed counties in the Midwestern US with low errors for both corn (R2 = 0.77; RMSE = 0.89 MT/ha and soybeans (R2 = 0.66; RMSE = 0.38 MT/ha. Because the proposed algorithm does not require any retrospective analysis that constructs empirical relationships between the reported yields and remotely sensed data, it could monitor crop yields over large areas.

Raw materials evaluation and process development studies for conversion of biomass to sugars and ethanol

Energy Technology Data Exchange (ETDEWEB)

Wilke, C.R.; Yang, R.D.; Sciamanna, A.S.; Freitas, R.P.

1978-06-01

A range of cellulosic raw materials in the form of agricultural crop residue was analyzed for chemical composition and assessed for potential yields of sugars through chemical pretreatment and enzymatic hydrolysis of these materials. Corn stover was used as a representative raw material for a preliminary process design and economic assessment of the production of sugars and ethanol. With the process as presently developed, 23 gallons of ethanol can be obtained per ton of corn stover at a processing cost of about $1.80 per gallon exclusive of by-product credits. The analysis shows the cost of ethanol to be highly dependent upon (1) the cost of the biomass, (2) the extent of conversion to glucose, (3) enzyme recovery and production cost and (4) potential utilization of xylose. Significant cost reduction appears possible through further research in these directions.

Improving conversion yield of fermentable sugars into fuel ethanol in 1st generation yeast-based production processes.

Science.gov (United States)

Gombert, Andreas K; van Maris, Antonius J A

2015-06-01

Current fuel ethanol production using yeasts and starch or sucrose-based feedstocks is referred to as 1st generation (1G) ethanol production. These processes are characterized by the high contribution of sugar prices to the final production costs, by high production volumes, and by low profit margins. In this context, small improvements in the ethanol yield on sugars have a large impact on process economy. Three types of strategies used to achieve this goal are discussed: engineering free-energy conservation, engineering redox-metabolism, and decreasing sugar losses in the process. Whereas the two former strategies lead to decreased biomass and/or glycerol formation, the latter requires increased process and/or yeast robustness. Copyright © 2014 Elsevier Ltd. All rights reserved.

Uncertainty in techno-economic estimates of cellulosic ethanol production due to experimental measurement uncertainty

Directory of Open Access Journals (Sweden)

Vicari Kristin J

2012-04-01

Full Text Available Abstract Background Cost-effective production of lignocellulosic biofuels remains a major financial and technical challenge at the industrial scale. A critical tool in biofuels process development is the techno-economic (TE model, which calculates biofuel production costs using a process model and an economic model. The process model solves mass and energy balances for each unit, and the economic model estimates capital and operating costs from the process model based on economic assumptions. The process model inputs include experimental data on the feedstock composition and intermediate product yields for each unit. These experimental yield data are calculated from primary measurements. Uncertainty in these primary measurements is propagated to the calculated yields, to the process model, and ultimately to the economic model. Thus, outputs of the TE model have a minimum uncertainty associated with the uncertainty in the primary measurements. Results We calculate the uncertainty in the Minimum Ethanol Selling Price (MESP estimate for lignocellulosic ethanol production via a biochemical conversion process: dilute sulfuric acid pretreatment of corn stover followed by enzymatic hydrolysis and co-fermentation of the resulting sugars to ethanol. We perform a sensitivity analysis on the TE model and identify the feedstock composition and conversion yields from three unit operations (xylose from pretreatment, glucose from enzymatic hydrolysis, and ethanol from fermentation as the most important variables. The uncertainty in the pretreatment xylose yield arises from multiple measurements, whereas the glucose and ethanol yields from enzymatic hydrolysis and fermentation, respectively, are dominated by a single measurement: the fraction of insoluble solids (fIS in the biomass slurries. Conclusions We calculate a $0.15/gal uncertainty in MESP from the TE model due to uncertainties in primary measurements. This result sets a lower bound on the error bars of

Climate change impacts on corn phenology and productivity

Science.gov (United States)

Climate is changing around the world and will impact future production of all food and feed crops. Corn is no exception to these impacts and to ensure a future supply of this vital crop we must begin to understand how climate impacts both the phenological development of corn and the productivity. Te...

Determination of Machining Parameters of Corn Byproduct Filled Plastics

Science.gov (United States)

In a collaborative project between the USDA and Northern Illinois University, the use of ethanol corn processing by-products as bio-filler materials in the compression molding of phenolic plastics has been studied. This paper reports on the results of a machinability study in the milling of various ...

Simultaneous saccharification and ethanol fermentation at high corn stover solids loading in a helical stirring bioreactor.

Science.gov (United States)

Zhang, Jian; Chu, Deqiang; Huang, Juan; Yu, Zhanchun; Dai, Gance; Bao, Jie

2010-03-01

The higher ethanol titer inevitably requires higher solids loading during the simultaneous enzymatic saccharification and fermentation (SSF) using lignocellulose as the feedstock. The mixing between the solid lignocellulose and the liquid enzyme is crucially important. In this study, a bioreactor with a novel helical impeller was designed and applied to the SSF operation of the steam explosion pretreated corn stover under different solids loadings and different enzyme dosages. The performances using the helical impeller and the common Rushton impeller were compared and analyzed by measuring rheological properties and the mixing energy consumption. The results showed that the new designed stirring system had better performances in the saccharification yield, ethanol titer, and energy cost than those of the Rushton impeller stirring. The mixing energy consumption under different solids loadings and enzyme dosages during SSF operation were analyzed and compared to the thermal energy in the ethanol produced. A balance for achieving the optimal energy cost between the increased mixing energy cost and the reduced distillation energy cost at the high solids loading should be made. The potentials of the new bioreactor were tested under various SSF conditions for obtaining optimal ethanol yield and titer. (c) 2009 Wiley Periodicals, Inc.

A comparison between corn and grain sorghum fermentation rates, distillers dried grains with solubles composition, and lipid profiles

Science.gov (United States)

Interest in utilization of feedstocks other than corn for fuel ethanol production has been increasing due to political as well as environmental reasons. Grain sorghum is an identified alternative that has a number of potential benefits relative to corn in both composition and agronomic traits. Compo...

Thermophilic, lignocellulolytic bacteria for ethanol production: current state and perspectives

DEFF Research Database (Denmark)

Chang, Tinghong; Yao, Shuo

2011-01-01

of cellulolytic and saccharolytic thermophilic bacteria for lignocellulosic ethanol production because of their unique properties. First of all, thermophilic bacteria possess unique cellulolytic and hemicellulolytic systems and are considered as potential sources of highly active and thermostable enzymes...... for efficient biomass hydrolysis. Secondly, thermophilic bacteria ferment a broad range of carbohydrates into ethanol, and some of them display potential for ethanologenic fermentation at high yield. Thirdly, the establishment of the genetic tools for thermophilic bacteria has allowed metabolic engineering......, in particular with emphasis on improving ethanol yield, and this facilitates their employment for ethanol production. Finally, different processes for second-generation ethanol production based on thermophilic bacteria have been proposed with the aim to achieve cost-competitive processes. However, thermophilic...

A constraint-based model of Scheffersomyces stipitis for improved ethanol production

Directory of Open Access Journals (Sweden)

Liu Ting

2012-09-01

Full Text Available Abstract Background As one of the best xylose utilization microorganisms, Scheffersomyces stipitis exhibits great potential for the efficient lignocellulosic biomass fermentation. Therefore, a comprehensive understanding of its unique physiological and metabolic characteristics is required to further improve its performance on cellulosic ethanol production. Results A constraint-based genome-scale metabolic model for S. stipitis CBS 6054 was developed on the basis of its genomic, transcriptomic and literature information. The model iTL885 consists of 885 genes, 870 metabolites, and 1240 reactions. During the reconstruction process, 36 putative sugar transporters were reannotated and the metabolisms of 7 sugars were illuminated. Essentiality study was conducted to predict essential genes on different growth media. Key factors affecting cell growth and ethanol formation were investigated by the use of constraint-based analysis. Furthermore, the uptake systems and metabolic routes of xylose were elucidated, and the optimization strategies for the overproduction of ethanol were proposed from both genetic and environmental perspectives. Conclusions Systems biology modelling has proven to be a powerful tool for targeting metabolic changes. Thus, this systematic investigation of the metabolism of S. stipitis could be used as a starting point for future experiment designs aimed at identifying the metabolic bottlenecks of this important yeast.

Cost evaluation of cellulase enzyme for industrial-scale cellulosic ethanol production based on rigorous Aspen Plus modeling.

Science.gov (United States)

Liu, Gang; Zhang, Jian; Bao, Jie

2016-01-01

Cost reduction on cellulase enzyme usage has been the central effort in the commercialization of fuel ethanol production from lignocellulose biomass. Therefore, establishing an accurate evaluation method on cellulase enzyme cost is crucially important to support the health development of the future biorefinery industry. Currently, the cellulase cost evaluation methods were complicated and various controversial or even conflict results were presented. To give a reliable evaluation on this important topic, a rigorous analysis based on the Aspen Plus flowsheet simulation in the commercial scale ethanol plant was proposed in this study. The minimum ethanol selling price (MESP) was used as the indicator to show the impacts of varying enzyme supply modes, enzyme prices, process parameters, as well as enzyme loading on the enzyme cost. The results reveal that the enzyme cost drives the cellulosic ethanol price below the minimum profit point when the enzyme is purchased from the current industrial enzyme market. An innovative production of cellulase enzyme such as on-site enzyme production should be explored and tested in the industrial scale to yield an economically sound enzyme supply for the future cellulosic ethanol production.

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

Science.gov (United States)

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.

Conversion of Lignocellulosic Biomass to Ethanol and Butyl Acrylate

Energy Technology Data Exchange (ETDEWEB)

Binder, Thomas [Archer Daniels Midland Company, Decatur, IL (United States); Erpelding, Michael [Archer Daniels Midland Company, Decatur, IL (United States); Schmid, Josef [Archer Daniels Midland Company, Decatur, IL (United States); Chin, Andrew [Archer Daniels Midland Company, Decatur, IL (United States); Sammons, Rhea [Archer Daniels Midland Company, Decatur, IL (United States); Rockafellow, Erin [Archer Daniels Midland Company, Decatur, IL (United States)

2015-04-10

Conversion of Lignocellulosic Biomass to Ethanol and Butyl Acrylate. The purpose of Archer Daniels Midlands Integrated Biorefinery (IBR) was to demonstrate a modified acetosolv process on corn stover. It would show the fractionation of crop residue to distinct fractions of cellulose, hemicellulose, and lignin. The cellulose and hemicellulose fractions would be further converted to ethanol as the primary product and a fraction of the sugars would be catalytically converted to acrylic acid, with butyl acrylate the final product. These primary steps have been demonstrated.

Separation of Corn Fiber and Conversion to Fuels and Chemicals Phase II: Pilot-scale Operation

Energy Technology Data Exchange (ETDEWEB)

Abbas, Charles; Beery, Kyle; Orth, Rick; Zacher, Alan

2007-09-28

The purpose of the Department of Energy (DOE)-supported corn fiber conversion project, “Separation of Corn Fiber and Conversion to Fuels and Chemicals Phase II: Pilot-scale Operation” is to develop and demonstrate an integrated, economical process for the separation of corn fiber into its principal components to produce higher value-added fuel (ethanol and biodiesel), nutraceuticals (phytosterols), chemicals (polyols), and animal feed (corn fiber molasses). This project has successfully demonstrated the corn fiber conversion process on the pilot scale, and ensured that the process will integrate well into existing ADM corn wet-mills. This process involves hydrolyzing the corn fiber to solubilize 50% of the corn fiber as oligosaccharides and soluble protein. The solubilized fiber is removed and the remaining fiber residue is solvent extracted to remove the corn fiber oil, which contains valuable phytosterols. The extracted oil is refined to separate the phytosterols and the remaining oil is converted to biodiesel. The de-oiled fiber is enzymatically hydrolyzed and remixed with the soluble oligosaccharides in a fermentation vessel where it is fermented by a recombinant yeast, which is capable of fermenting the glucose and xylose to produce ethanol. The fermentation broth is distilled to remove the ethanol. The stillage is centrifuged to separate the yeast cell mass from the soluble components. The yeast cell mass is sold as a high-protein yeast cream and the remaining sugars in the stillage can be purified to produce a feedstock for catalytic conversion of the sugars to polyols (mainly ethylene glycol and propylene glycol) if desirable. The remaining materials from the purification step and any materials remaining after catalytic conversion are concentrated and sold as a corn fiber molasses. Additional high-value products are being investigated for the use of the corn fiber as a dietary fiber sources.

U.S. Ethanol Demand and World Hunger: Is There Any Connection?

OpenAIRE

Hao, Na; Colson, Greg; Wetzstein, Michael

2015-01-01

U.S. ethanol expansion objectives are to improve both energy security and the environmental. However, this expansion has raised issues concerning its detrimental impacts on the price volatility of developing countries’ agricultural commodities. These concerns are addressed by empirically investigating the relations among U.S. ethanol and corn markets with developing countries’ corn prices. Results indicate that U.S. ethanol demand impacts on developing countries’ corn prices vary by country. ...

Ethanol Demand in United States Gasoline Production

Energy Technology Data Exchange (ETDEWEB)

Hadder, G.R.

1998-11-24

The Oak Ridge National Laboratory (OWL) Refinery Yield Model (RYM) has been used to estimate the demand for ethanol in U.S. gasoline production in year 2010. Study cases examine ethanol demand with variations in world oil price, cost of competing oxygenate, ethanol value, and gasoline specifications. For combined-regions outside California summer ethanol demand is dominated by conventional gasoline (CG) because the premised share of reformulated gasoline (RFG) production is relatively low and because CG offers greater flexibility for blending high vapor pressure components like ethanol. Vapor pressure advantages disappear for winter CG, but total ethanol used in winter RFG remains low because of the low RFG production share. In California, relatively less ethanol is used in CG because the RFG production share is very high. During the winter in California, there is a significant increase in use of ethanol in RFG, as ethanol displaces lower-vapor-pressure ethers. Estimated U.S. ethanol demand is a function of the refiner value of ethanol. For example, ethanol demand for reference conditions in year 2010 is 2 billion gallons per year (BGY) at a refiner value of $1.00 per gallon (1996 dollars), and 9 BGY at a refiner value of $0.60 per gallon. Ethanol demand could be increased with higher oil prices, or by changes in gasoline specifications for oxygen content, sulfur content, emissions of volatile organic compounds (VOCS), and octane numbers.

Asymmetric Adjustment in the Ethanol and Grains Markets

NARCIS (Netherlands)

C-L. Chang (Chia-Lin); L.H. Chen (Li-Hsueh); S.M. Hammoudeh (Shawkat); M.J. McAleer (Michael)

2011-01-01

textabstractThis paper examines the long- and short-run asymmetric adjustments for nine pairs of spot and futures prices, itemized as three own pairs for three different bio-fuel ethanol types, three own pairs for three related agricultural products, namely corn, soybeans and sugar, and three cross

Corn stover for advanced biofuels perspectives of a soil “Lorax”

Science.gov (United States)

Crop residues like corn (Zea Mays L) stover are potential feedstock for production of advanced biofuels (e.g., cellulosic ethanol). Utilization of residue like stover for biofuel feedstock may provide economic and greenhouse gas mitigation benefits; however, harvesting these materials must be done i...

The U2U Corn Growing Degree Day tool: Tracking corn growth across the US Corn Belt

Directory of Open Access Journals (Sweden)

James R. Angel

2017-01-01

Full Text Available The Corn Growing Degree Day (Corn GDD tool is a web-based product that can provide decision support on a variety of issues throughout the entire growing season by integrating current conditions, historical climate data, and projections of Corn GDD through the end of the growing season based on both National Weather Service computer model forecasts and climatology. The Corn GDD tool can help agricultural producers make a variety of important decisions before and during the growing season. This support can include: assessing the risk of early and late frosts and freezes that can cause crop damage; comparing corn hybrid maturity requirements and Corn GDD projections to select seed varieties and plan activities such as spraying; guiding marketing decisions based on historical and projected Corn GDDs when considering forward crop pricing (i.e., futures market. The Corn GDD tool provides decision support for corn producers in the central U.S. corn-producing states. Survey results, web statistics, and user feedback indicate that this tool is being actively used by decision makers.

Ethanol Basics (Fact Sheet)

Energy Technology Data Exchange (ETDEWEB)

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.

SWEET CORN FARMING: THE EFFECT OF PRODUCTION FACTOR, EFFICIENCY AND RETURN TO SCALE

Directory of Open Access Journals (Sweden)

Dwijatenaya I.B.M.A.

2017-10-01

Full Text Available This research aims to determine the effect of production factors on the sweet corn production, the efficiency of sweet corn farming, and the return to scale of sweet corn production. The sampling technique was taken by proportionate stratified random sampling method with the sample number of 57 people while the analyzer used was the program of Frointer 4.1c. The results show that the production factors of the land farm, seed, and fertilizer have a positive and significant effect on sweet corn production. On the other hand, labor production factors have a positive but not significant effect on sweet corn production. It also found that technical efficiency, price efficiency, and economic efficiency of sweet corn farming in Muara Wis Sub-district of Kutai Kartanegara Regency are not efficient yet. The return to scale of sweet corn yield has an increasing return to scale condition.

Improving hybrid seed production in corn with glyphosate-mediated male sterility.

Science.gov (United States)

Feng, Paul C C; Qi, Youlin; Chiu, Tommy; Stoecker, Martin A; Schuster, Christopher L; Johnson, Scott C; Fonseca, Augustine E; Huang, Jintai

2014-02-01

Hybrid corn varieties exhibit benefits associated with heterosis and account for most of the corn acreage in the USA. Hybrid seed corn is produced by crossing a female parent which is male-sterile and therefore incapable of self-pollination with a male parent as the pollen donor. The majority of hybrid seed corn is produced by mechanical detasseling which involves physically removing the tassel, a process that is laborious and costly. Glyphosate-resistant corn was developed via expression of a glyphosate insensitive 5-enolpyruvyl-shikimate 3-phosphate synthase enzyme (CP4-EPSPS). Experimentation with molecular expression elements resulted in selective reduction of CP4-EPSPS expression in male reproductive tissues. The resulting plant demonstrated sterile tassel following glyphosate application with little to no injury to the rest of the plant. Using (14)C-glyphosate as a marker, we also examined the translocation of glyphosate to the tassel via spray application in a track sprayer to simulate field application. The results allowed optimization of spray parameters such as dose, spray timing and target to maximize tassel delivery of glyphosate for efficient sterilization. The Roundup hybridization system (RHS) is a novel process for hybrid seed production based on glyphosate-mediated male sterility. RHS replaces mechanical detasseling with glyphosate spray and greatly simplifies the process of hybrid seed corn production. © 2013 Society of Chemical Industry.

Rewiring Lactococcus lactis for Ethanol Production

DEFF Research Database (Denmark)

Solem, Christian; Dehli, Tore Ibsen; Jensen, Peter Ruhdal

2013-01-01

to redirect the metabolism of LAB model organism Lactococcus lactis toward ethanol production. Codon-optimized Zymomonas mobilis pyruvate decarboxylase (PDC) was introduced and expressed from synthetic promoters in different strain backgrounds. In the wild-type L. lactis strain MG1363 growing on glucose, only...... small amounts of ethanol were obtained after introducing PDC, probably due to a low native alcohol dehydrogenase activity. When the same strains were grown on maltose, ethanol was the major product and lesser amounts of lactate, formate, and acetate were formed. Inactivating the lactate dehydrogenase...... genes ldhX, ldhB, and ldh and introducing codon-optimized Z. mobilis alcohol dehydrogenase (ADHB) in addition to PDC resulted in high-yield ethanol formation when strains were grown on glucose, with only minor amounts of by-products formed. Finally, a strain with ethanol as the sole observed...

Dietary fructose augments ethanol-induced liver pathology.

Science.gov (United States)

Thomes, Paul G; Benbow, Jennifer H; Brandon-Warner, Elizabeth; Thompson, Kyle J; Jacobs, Carl; Donohue, Terrence M; Schrum, Laura W

2017-05-01

Certain dietary components when combined with alcohol exacerbate alcohol-induced liver injury (ALI). Here, we tested whether fructose, a major ingredient of the western diet, enhances the severity of ALI. We fed mice ethanol for 8 weeks in the following Lieber-DeCarli diets: (a) Regular (contains olive oil); (b) corn oil (contains corn oil); (c) fructose (contains fructose and olive oil) and (d) corn+fructose (contains fructose and corn oil). We compared indices of metabolic function and liver pathology among the different groups. Mice fed fructose-free and fructose-containing ethanol diets exhibited similar levels of blood alcohol, blood glucose and signs of disrupted hepatic insulin signaling. However, only mice given fructose-ethanol diets showed lower insulin levels than their respective controls. Compared with their respective pair-fed controls, all ethanol-fed mice exhibited elevated levels of serum ALT; the inflammatory cytokines TNF-α, MCP-1 and MIP-2; hepatic lipid peroxides and triglycerides. All the latter parameters were significantly higher in mice given fructose-ethanol diets than those fed fructose-free ethanol diets. Mice given fructose-free or fructose-containing ethanol diets each had higher levels of hepatic lipogenic enzymes than controls. However, the level of the lipogenic enzyme fatty acid synthase (FAS) was significantly higher in livers of mice given fructose control and fructose-ethanol diets than in all other groups. Our findings indicate that dietary fructose exacerbates ethanol-induced steatosis, oxidant stress, inflammation and liver injury, irrespective of the dietary fat source, to suggest that inclusion of fructose in or along with alcoholic beverages increases the risk of more severe ALI in heavy drinkers. Copyright © 2017 Elsevier Inc. All rights reserved.

Analysis of Maize versus Ethanol Production in Nebraska, United States and International Agricultural Droughts: Lessons for Global Food Security

Science.gov (United States)

Boken, V.; Tenkorang, F.

2012-04-01

Nebraska is one of the eight main corn (maize) belt states of the United States. Maize is the major crop of Nebraska with an average annual production of about 38 million tons (about 12% of U.S. production), which contributes billions of dollars to the state's economy. The yield of maize has increased significantly over the past century - from 1.6 t/ha in 1900 to 10.4 t/ha in 2010. While the majority of maize (about 40%) is currently used for animal feed and ethanol production, only about six percent is exported. It is estimated that about one billion people accounting for about 15% population of the world live in chronic hunger because of low agricultural productivity and drought. Most of these people depend on the U.S. for grains including maize. If a greater quantity of maize is diverted to ethanol production, considerably less quantity of maize would be available for export to developing countries where it could be used for human consumption and to mitigate hunger and improve food security. This paper presents analysis of maize production in Nebraska for the past three decades and examines how its commercialization for ethanol production has affected its exports in the face of drought at an international level.

The possibility of drought risk reduction in corn production

Directory of Open Access Journals (Sweden)

Pajić Nemanja

2016-01-01

Full Text Available Weather derivatives are contemporary instruments for insurance risk of drought in agricultural production. Corn production is particularly sensitive to this risk, and the amount of the yield of this crop is in significant correlation with the July-August rainfall amount. Oscillations of production output, caused by the risk of drought, are reflected directly on the fluctuations of the financial result. The application of weather derivatives may decrease the variability of the mentioned economic parameter in corn production. In the investigated example of corn production, simulating the application of the weather option the coefficient of variation of realized financial results decreased by 9.64% compared to the version without the insured risk. At the same time, using the analysed insurance instrument, the risk of achieving a negative financial result is eliminated.

The addition of sugar beet to ethanol pathway in GHGenius

International Nuclear Information System (INIS)

2007-01-01

Developed by Natural Resources Canada, the GHGenius model is used to estimate the life cycle emissions of primary greenhouse gases (GHGs) as well as the criteria pollutants from combustion sources. The model can be used to analyze the emissions from conventional and alternatively fuelled combustion engines and fuel cell powered trucks and vehicles, as well as light duty powered electric vehicles. Over 140 vehicle and fuel combinations can be used. This paper examined the effects of adding energy used to produce materials consumed in the production of alternative fuels in GHGenius energy balance calculations, as well as vehicle emission calculations on a carbon dioxide (CO 2 ) eq/GJ of fuel consumed basis. This paper also examined the addition of sugar beet ethanol pathways to GHGenius. Energy balances were obtained and a number of process improvements to sugar beet ethanol processing were examined as sensitivity cases. GHGenius was used to calculate the energy consumption of each stage in the production cycle. Estimates included the energy required to produce the chemicals used in the ethanol processing procedure. Results were then compared with results obtained from gasoline, corn and wheat ethanols. Results of the study showed that energy balances were lower than corn or wheat ethanol. Feedstock transmission and processing requirements were also higher due to the higher moisture content of the feedstock. The results of several European studies considering the use of sugar beet ethanol were also included. 17 tabs., 9 figs

Maleic acid treatment of biologically detoxified corn stover liquor.

Science.gov (United States)

Kim, Daehwan; Ximenes, Eduardo A; Nichols, Nancy N; Cao, Guangli; Frazer, Sarah E; Ladisch, Michael R

2016-09-01

Elimination of microbial and enzyme inhibitors from pretreated lignocellulose is critical for effective cellulose conversion and yeast fermentation of liquid hot water (LHW) pretreated corn stover. In this study, xylan oligomers were hydrolyzed using either maleic acid or hemicellulases, and other soluble inhibitors were eliminated by biological detoxification. Corn stover at 20% (w/v) solids was LHW pretreated LHW (severity factor: 4.3). The 20% solids (w/v) pretreated corn stover derived liquor was recovered and biologically detoxified using the fungus Coniochaeta ligniaria NRRL30616. After maleic acid treatment, and using 5 filter paper units of cellulase/g glucan (8.3mg protein/g glucan), 73% higher cellulose conversion from corn stover was obtained for biodetoxified samples compared to undetoxified samples. This corresponded to 87% cellulose to glucose conversion. Ethanol production by yeast of pretreated corn stover solids hydrolysate was 1.4 times higher than undetoxified samples, with a reduction of 3h in the fermentation lag phase. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ethanol production from rape straw: Part of an oilseed rape biorefinery

DEFF Research Database (Denmark)

Arvaniti, Efthalia

The aim of this study was 1) present an oilseed rape whole crop biorefinery; 2) to investigate the best available experimental conditions for production of cellulosic ethanol from rape straw, and included the processes of thermo-chemical pretreatment, enzymatic hydrolysis, and C6 fermentation......, and 3) to couple cellulosic ethanol production to production of cellulolytic enzymes that are needed for cellulosic ethanol production, inside a rape straw biorefinery. For the first is based less on available experiments, and more on literature review. The second and third study conclusions were drawn...... rapeseed biodiesel plant of Europe to an oilseed rape whole-crop biorefinery by 2020 is envisioned and discussed. The description and discussion of this biorefinery is based partly on literature review, and partly on own experimental data, especially on pretreatment of rape straw, and production...

Comparative effects of dietary corn oil, safflower oil, fish oil and palm oil on metabolism of ethanol and carnitine in the rat.

Science.gov (United States)

Sachan, Dileep S; Yatim, Ayub M; Daily, James W

2002-06-01

This study was launched to determine comparative effects of corn oil (CO), safflower oil (SO), fish oil (FO) and palm oil (PO) on carnitine status and ethanol metabolism in rats. Twenty-four male Sprague-Dawley rats (300 g bw) were randomly divided into four groups (n = 6) and fed a semisynthetic diets containing fat as oils listed above. Blood and 24 hour urine samples were collected before and after dietary treatment and acute ethanol administration. Samples were analyzed for blood-ethanol concentration (BEC) and carnitine species. The diets containing FO and PO retarded ethanol metabolism compared to the diets containing CO and SO. The effect of these dietary fats on carnitine species in plasma and urine was varied before and after dietary treatment and following a single oral ethanol dose. The liver carnitine content was higher in the PO group after dietary and ethanol treatment. It is concluded that attenuation of ethanol clearance was related to unique fatty acid makeup of the oils that in part may be attributed to the composite ratio of saturated to unsaturated fatty acids in the oils.

Sustainability of grape-ethanol energy chain

Directory of Open Access Journals (Sweden)

Ester Foppa Pedretti

2014-11-01

Full Text Available The aim of this work is to evaluate the sustainability, in terms of greenhouse gases emission saving, of a new potential bio-ethanol production chain in comparison with the most common ones. The innovation consists of producing bio-ethanol from different types of no-food grapes, while usually bio-ethanol is obtained from matrices taken away from crop for food destination: sugar cane, corn, wheat, sugar beet. In the past, breeding programs were conducted with the aim of improving grapevine characteristics, a large number of hybrid vine varieties were produced and are nowadays present in the Viticulture Research Centre (CRA-VIT Germplasm Collection. Some of them are potentially interesting for bio-energy production because of their high production of sugar, good resistance to diseases, and ability to grow in marginal lands. Life cycle assessment (LCA of grape ethanol energy chain was performed following two different methods: i using the spreadsheet BioGrace, developed within the Intelligent Energy Europe program to support and to ease the Renewable Energy Directive 2009/28/EC implementation; ii using a dedicated LCA software. Emissions were expressed in CO2 equivalent (CO2eq. These two tools gave very similar results. The overall emissions impact of ethanol production from grapes on average is about 33 g CO2eq MJ–1 of ethanol if prunings are used for steam production and 53 g CO2eq MJ–1 of ethanol if methane is used. The comparison with other bio-energy chains points out that the production of ethanol using grapes represents an intermediate situation in terms of general emissions among the different production chains. The results showed that the sustainability limits provided by the normative are respected to this day. On the contrary, from 2017 this production will be sustainable only if the transformation processes will be performed using renewable sources of energy.

Environmental aspects of ethanol-based fuels from Brassica carinata. A case study of second generation ethanol

International Nuclear Information System (INIS)

Gonzalez-Garcia, Sara; Moreira, M'a Teresa; Feijoo, Gumersindo; Gasol, Carles M.; Gabarrell, Xavier; Rieradevall, Joan

2009-01-01

One of the main challenges faced by mankind in the 21st century is to meet the increasing demand for energy requirements by means of a more sustainable energy supply. In countries that are net fossil fuel importers, expectation about the benefit of using alternative fuels on reducing oil imports is the primary driving force behind efforts to promote its production and use. Spain is scarce in domestic energy sources and more than 50% of the energy used is fossil fuel based. The promotion of renewable energies use is one of the principal vectors in the Spanish energy policy. Selected herbaceous crops such as Brassica carinata are currently under study as potential energy sources. Its biomass can be considered as potential feedstock to ethanol conversion by an enzymatic process due to the characteristics of its composition, rich in cellulose and hemicellulose. This paper aims to analyse the environmental performance of two ethanol-based fuel applications (E10 and E85) in a passenger car (E10 fuel: a mixture of 10% ethanol and 90% gasoline by volume; E85 fuel: a mixture of 85% ethanol and 15% gasoline by volume) as well as their comparison with conventional gasoline as transport fuel. Two types of functional units are applied in this study: ethanol production oriented and travelling distance oriented functional units in order to reflect the availability or not of ethanol supply. E85 seems to be the best alternative when ethanol production based functional unit is considered in terms of greenhouse gas (GHG) emissions and E10 in terms of non-renewable energy resources use. Nevertheless, E85 offers the best environmental performance when travelling distance oriented functional unit is assumed in both impacts. In both functional unit perspectives, the use of ethanol-based fuels reduces the global warming and fossil fuels consumption. However, the contributions to other impact indicators (e.g. acidification, eutrophication and photochemical oxidants formation) were lower

Willingness to pay for E85 from corn, switchgrass, and wood residues

Energy Technology Data Exchange (ETDEWEB)

Jensen, Kimberly L.; Clark, Christopher D.; English, Burton C.; Menard, R. Jamey; Skahan, Denise K.; Marra, Adrienne C. [Department of Agricultural Economics, The University of Tennessee, 302 Morgan Hall, Knoxville, TN, 37996 (United States)

2010-11-15

Willingness to pay (WTP) for E85 (automotive fuel blend of 85% ethanol and 15% gasoline) was estimated from a contingent choice exercise contained in a national survey of consumers. The choice exercise included E85 blends from three different feedstock sources (corn grain, switchgrass, and wood wastes) and an E10 blend (10% ethanol and 90% gasoline) with corn grain as the ethanol feedstock. Results from the study indicate willingness to pay a premium for E85 from switchgrass compared with E10 from corn. Concerns about land use for ''food versus fuel'' had a negative impact on WTP for E85 from corn grain, while greater concerns about fuel security relative to the environment had a positive impact. (author)

Willingness to pay for E85 from corn, switchgrass, and wood residues

International Nuclear Information System (INIS)

Jensen, Kimberly L.; Clark, Christopher D.; English, Burton C.; Menard, R. Jamey; Skahan, Denise K.; Marra, Adrienne C.

2010-01-01

Willingness to pay (WTP) for E85 (automotive fuel blend of 85% ethanol and 15% gasoline) was estimated from a contingent choice exercise contained in a national survey of consumers. The choice exercise included E85 blends from three different feedstock sources (corn grain, switchgrass, and wood wastes) and an E10 blend (10% ethanol and 90% gasoline) with corn grain as the ethanol feedstock. Results from the study indicate willingness to pay a premium for E85 from switchgrass compared with E10 from corn. Concerns about land use for ''food versus fuel'' had a negative impact on WTP for E85 from corn grain, while greater concerns about fuel security relative to the environment had a positive impact. (author)

Cellulose conversion of corn pericarp without pretreatment.

Science.gov (United States)

Kim, Daehwan; Orrego, David; Ximenes, Eduardo A; Ladisch, Michael R

2017-12-01

We report enzyme hydrolysis of cellulose in unpretreated pericarp at a cellulase loading of 0.25FPU/g pericarp solids using a phenol tolerant Aspergillus niger pectinase preparation. The overall protein added was 5mg/g and gave 98% cellulose conversion in 72h. However, for double the amount of enzyme from Trichoderma reesei, which is significantly less tolerant to phenols, conversion was only 16%. The key to achieving high conversion without pretreatment is combining phenol inhibition-resistant enzymes (such as from A. niger) with unground pericarp from which release of phenols is minimal. Size reduction of the pericarp, which is typically carried out in a corn-to-ethanol process, where corn is first ground to a fine powder, causes release of highly inhibitory phenols that interfere with cellulase enzyme activity. This work demonstrates hydrolysis without pretreatment of large particulate pericarp is a viable pathway for directly producing cellulose ethanol in corn ethanol plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of ethanol productivity from cellulose by Clostridium thermocellum

Energy Technology Data Exchange (ETDEWEB)

Kurose, N; Yagyu, J; Miyazaki, T; Uchida, M; Hanai, S; Obayashi, A

1986-01-01

Clostridium thermocellum, a thermophilic anaerobe, directly converts cellulose to EtOH. To estimate its EtOH production from cellulose, we used a new method based on material balance by which the efficiencies of the enzymes that convert cellulose to ethanol were calculated. Using this method, the maximum efficiency of ethanol production of two strains of C. thermocellum was estimated to be 0.05, with 0.67 as the theoretical maximum. 3 references.

Ethanol Production from Different Intermediates of Sugar Beet Processing

Directory of Open Access Journals (Sweden)

Mladen Pavlečić

2010-01-01

Full Text Available In this investigation, the production of ethanol from the raw sugar beet juice and raw sugar beet cossettes has been studied. For ethanol production from the raw sugar beet juice, batch and fed-batch cultivation techniques in the stirred tank bioreactor were used, while batch ethanol production from the raw sugar beet cossettes was carried out in horizontal rotating tubular bioreactor (HRTB. In both cases, Saccharomyces cerevisiae was used as a production microorganism. During batch ethanol production from the raw sugar beet juice, ethanol yield was 59.89 g/L and production efficiency 78.8 %, and in fed-batch process the yield was 92.78 g/L and efficiency 93.4 %. At the same time, ethanol production in HRTB from the raw sugar beet cossettes with inoculum of 16.7 % V/m (raw sugar beet cossettes resulted in the highest ethanol yield of 54.53 g/L and production efficiency of 79.5 %. The obtained results clearly show that both intermediates of sugar beet processing can be successfully used for ethanol production.

Life cycle cost of ethanol production from cassava in Thailand

International Nuclear Information System (INIS)

Sorapipatana, Chumnong; Yoosin, Suthamma

2011-01-01

To increase the security of energy supply, lessen dependence on crude oil import and buffer against the impacts of large change in crude oil prices, the Thai government initiated and officially announced the national ethanol fuel program in year 2000. Since then, domestic ethanol demand has grown rapidly. Presently, all commercial ethanol in Thailand is produced from molasses as Thai law prohibits producing it from sugar cane directly. This is likely to limit ethanol supply in the near future. One possible solution is to supply more ethanol from cassava which is widely cultivated in this country. However, its production cost has not yet been known for certain. The objective of this study is to estimate the life cycle cost of ethanol production from cassava and to assess its economic competitiveness with gasoline in the Thai fuel market. Based on the record of cassava prices during the years 2002-2005, it was found that using it as feedstock would share more than 50% of the ethanol from cassava total production cost. It was also found that a bio-ethanol plant, with a capacity of 150,000 l/day, can produce ethanol from cassava in a range of ex-factory costs from 16.42 to 20.83 baht/l of gasoline equivalent (excluding all taxes), with an average cost of 18.15 baht/l of gasoline equivalent (41, 52 and 45 US cents/l gasoline equivalent respectively, based on 2005 exchange rate). In the same years, the range of 95-octane gasoline prices in Thailand varied from 6.18 baht to 20.86 baht/l, with an average price of 11.50 baht/l (15, 52 and 29 US cents/l respectively, based on 2005 exchange rate) which were much cheaper than the costs of ethanol made from cassava. Thus, we conclude that under the scenario of low to normal crude oil price, ethanol from cassava is not competitive with gasoline. The gasoline price has to rise consistently above 18.15 baht (45 US cents)/l before ethanol made from cassava can be commercially competitive with gasoline. (author)

Life cycle cost of ethanol production from cassava in Thailand

Energy Technology Data Exchange (ETDEWEB)

Sorapipatana, Chumnong; Yoosin, Suthamma [Joint Graduate School of Energy and Environment, King Mongkut' s University of Technology Thonburi, Pracha-Uthit Rd., Tungkru, Bangmod, Bangkok 10140 (Thailand); Center for Energy Technology and Environment, Commission on Higher Education, Ministry of Education, Bangkok (Thailand)

2011-02-15

To increase the security of energy supply, lessen dependence on crude oil import and buffer against the impacts of large change in crude oil prices, the Thai government initiated and officially announced the national ethanol fuel program in year 2000. Since then, domestic ethanol demand has grown rapidly. Presently, all commercial ethanol in Thailand is produced from molasses as Thai law prohibits producing it from sugar cane directly. This is likely to limit ethanol supply in the near future. One possible solution is to supply more ethanol from cassava which is widely cultivated in this country. However, its production cost has not yet been known for certain. The objective of this study is to estimate the life cycle cost of ethanol production from cassava and to assess its economic competitiveness with gasoline in the Thai fuel market. Based on the record of cassava prices during the years 2002-2005, it was found that using it as feedstock would share more than 50% of the ethanol from cassava total production cost. It was also found that a bio-ethanol plant, with a capacity of 150,000 l/day, can produce ethanol from cassava in a range of ex-factory costs from 16.42 to 20.83 baht/l of gasoline equivalent (excluding all taxes), with an average cost of 18.15 baht/l of gasoline equivalent (41, 52 and 45 US cents/l gasoline equivalent respectively, based on 2005 exchange rate). In the same years, the range of 95-octane gasoline prices in Thailand varied from 6.18 baht to 20.86 baht/l, with an average price of 11.50 baht/l (15, 52 and 29 US cents/l respectively, based on 2005 exchange rate) which were much cheaper than the costs of ethanol made from cassava. Thus, we conclude that under the scenario of low to normal crude oil price, ethanol from cassava is not competitive with gasoline. The gasoline price has to rise consistently above 18.15 baht (45 US cents)/l before ethanol made from cassava can be commercially competitive with gasoline. (author)