Corn-based Ethanol Production Research Articles

Determination of apparent and standardized ileal digestibility of amino acids in corn HP-DDG fed to growing pigs

The corn-based ethanol production industry provides co-products with potential value as animal feed. However, the nutritional value of these co-products should be adequately determined for their sustainable implementation in swine diets. Therefore, a study was conducted to determine the concentration of amino acids (AA), apparent ileal digestible amino acids (AID), standardized ileal digestible amino acids (SID), and crude protein (CP) in corn distillers dried grains with high protein content (corn HP-DDG) for pigs. Six growing pigs (initial body weight: 46.30 ± 2.14 kg) were surgically fitted with a T-cannula at the distal ileum and allotted to a duplicate 2 × 3 incomplete Latin Square Design. Diets containing corn HP-DDG as the only AA source and a nitrogen-free diet (NFD) were formulated. Corn HP-DDG was used as a test ingredient to replace 40% of the starch in NFD, and titanium dioxide (0.5%) was added as an indigestible marker to both diets. Pigs were fed between 08:00 and 18:00 h during five days of adaptation and a sequence of two days of ileal digesta collection. On an as-fed basis, the chemical composition of corn HP-DDG was 40.41% CP, 1.39% lysine, 1.57% methionine + cysteine, 1.61% threonine, 0.23% tryptophan, and 2.15% valine. The AID and SID values of corn HP-DDG were 74.04% and 80.87% for CP; 76.32% and 79.15% for lysine; 84.75% and 86.52% for methionine + cysteine; 71.97% and 78.30% for threonine; 83.86% and 92.44% for tryptophan; and 76.34% and 80.47% for valine, respectively. In conclusion, the SID CP and AA in corn HP-DDG were within the previously published values, and the determined SID coefficients should be used to formulate accurate diets for pigs.

Assessing Ionizing Radiation and Chlorine Dioxide (ClO2) as Potential Aseptization Treatments for Yeast Recycling on Mixed Wort of Corn and Sugarcane in Brazil

Yeast recycling, which is a common practice in sugarcane ethanol plants, could be expanded if it could be successfully implemented in corn-based ethanol production. However, the process of recycling the yeast remaining after fermentation is hampered by contaminating microorganisms that reduce the fermentation efficiency and compete with the yeast for the fermentable sugars. Currently, antibiotics are used to control microbial contamination. This study proposes chlorine dioxide and electron beam irradiation as alternative control methods for completely inactivating contaminants and minimizing their effect on recycled yeast. For that, wort sterilization using electron radiation (20 kGy) and treatment with a chemical biocide, namely chlorine dioxide (125 mg kg−1), were compared with non-treated wort. Five fermentation cycles were performed using fed-batch systems with 300 g L−1 of fermentable sugars. The results obtained in this study showed the inactivation of contaminants under the effect of electron beam irradiation, which led to an increase in the productivity, yield, and efficiency of fermentation by 0.21 g L−1h−1, 2.6%, and 4.7%, respectively. However, ClO2 did not show promising results in reducing contamination or improving fermentative parameters. Thus, electron beam irradiation of contaminated wort may be a suitable alternative to chemical biocides and would allow the use of recycled yeast in corn-based ethanol plants.

Foresight for corn-to-ethanol mills in the Southern Brazilian Amazon: Energy, economic and environmental analysis

A sustainable expansion of corn-based and sugarcane-based ethanol production could induce food safety and also decrease the Southern Brazilian Amazon’s extensive cattle farming and deforestation of new pasture areas. The present work aims to evaluate a technological prospect regarding the strategies and market potential of bioenergy and bio-products generation for a corn-based production system. A ‘Strategic Foresight’ approach was formulated and thoroughly analyzed. Overall, it showed that productivity improvement of livestock could be accomplished, and light vehicles’ energy demand using anhydrous and hydrous ethanol could also be enhanced. The results demonstrated that greenhouse gas emissions from a ‘Corn-to-Ethanol’ production system are smaller than the conventional Mills. The Foresight analysis identified that the positive energy balance from ethanol provides more energy than its industrial consumption. ‘Corn Ethanol’ production processes are integrated in six (6) “Flex Mills” in Brazil by taking advantage of the existing installations for sugarcane processing with a production ranging from 250 to 500 million liters/year. The State of Mato Grosso shall have twelve (12) Ethanol Mills in “Full” operation until 2021. The SWOT analysis in this study revealed that: the economy's development could generate direct and indirect jobs, potentially supporting the energy transition to a low-carbon economy through the valorization of agricultural and livestock products, and thus allowing the expansion of confined livestock, pig, and fish farming. Finally, the Strategic Foresight showed the multi-tiered importance of technological application and cooperation in the agro-industrial sector.

Impacts of Ethanol Production and Drying Conditions on the Chemical, Physical, and Flowability Properties of Distillers Dried Grains With Solubles.

The production of corn-based ethanol in the U.S. has dramatically increasied in recent years, and consequently so has the quantity of coproduct feed ingredients generated from this segment of the grain processing industry. These streams are almost exclusively utilized as livestock feed, which partially offsets the need for corn in feed rations, but other value-added applications do exist. Because of its use as an animal feed, considerable research has been conducted into the nutritional properties, but to a lesser extent the physical and flowability properties of commercially-produced distillers dried grains with solubles (DDGS). There can be occasions when the quality of coproducts is not consistent. Thus questions regarding the influence of processing operations on the resulting coproduct characteristics must be examined. The objective of this research was to conduct extensive physical and flowability property analyses on DDGS samples which were produced under varying conditions in a pilot plant-scale ethanol plant, in order to investigate the effects of various manufacturing operations (specifically ethanol production and drying conditions) on the resulting properties of the DDGS. Using various laboratory methods, a variety of properties, including bulk density and angle of repose, were determined. DDGS fat content was highly correlated with aerated and packed bulk densities, which indicates that fat level plays a key role in flowability behavior. Future studies should examine this potential relationship in more depth, especially as the industry has moved to fat reduction via oil separation processes.

Techno-Economic Analysis of Integrating Soybean Biorefinery Products into Corn-Based Ethanol Fermentation Operations

With the development of agricultural biorefineries and bioprocessing operations, understanding the economic efficiencies and environmental impacts for these have gradually become popular for the deployment of these industrial processes. The corn-based ethanol and soybean oil refining industries have been examined extensively over the years, especially details of processing technologies, including materials, reaction controls, equipment, and industrial applications. The study focused on examining the production efficiency changes and economic impacts of integrating products from the enzyme-assisted aqueous extraction processing (EAEP) of soybeans into corn-based ethanol fermentation processing. Using SuperPro Designer to simulate production of corn-based ethanol at either 40 million gallons per year (MGY) or 120 MGY, with either oil separation or no oil removal, we found that indeed integrating soy products into corn ethanol fermentation may be slightly more expensive in terms of production costs, but economic returns justify this integration due to substantially greater quantities of ethanol, distillers corn oil, and distillers dried grains with solubles being produced.

Simulation-Based Capacity Planning of a Biofuel Refinery

The reduction in the operational cost of a biofuel refinery is vitally important to make biofuel competitive with fossil fuels. The aim of this paper is to find a cost-efficient and sustainable refinery capacity for grain-based ethanol (i.e., corn-based ethanol) production, which will play an important role in promoting the widespread adoption and sustainable use of ethanol, by improving the productivity of the overall refining process. Continuous-event simulation was utilized in this study to model complex operations of a refinery such as the loading, unloading and treatment of feedstock over nine major phases (e.g., feedstock storage and handling, pretreatment and conditioning, fermentation and hydrolysis, and enzyme production) to produce ethanol. To improve the model prediction, the real data of corn yield produced in Tazewell County, Illinois, U.S. were used. The proposed simulation model is implemented in AnyLogic® University 8.6.0 simulation software, Chicago, IL, USA, and the (near) optimal number of reactors for the hydrolysis and fermentation is found via optimization software known as OptQuest®, Boulder, CO, USA, As a result, the proposed approach found that six reactors showed the optimal daily profit from USD 67,500 to 82,217. This information will help engineers and policy makers to modify the capacity of a biofuel refinery for enhancement of the system efficiency and ethanol production.

Formulation of Broiler Chicken Feeds Using Distillers Dried Grains with Solubles

Distillers dried grains with solubles (DDGS) is a coproduct of corn-based ethanol production that can be a valuable source of energy, digestible amino acids, and available phosphorus in poultry feeds. Dietary incorporation of DDGS reduces the amount of primary ingredients such as corn and soybean meal needed to formulate poultry diets, improving the sustainability of both biofuel and poultry production. The nutritional value of DDGS has been extensively evaluated since it became increasingly available to feed producers in the early 2000s, but evolving methods of ethanol production and coproduct fractionation necessitate its continued characterization. Attempts to relate nutrient utilization of DDGS to its chemical composition have revealed that fiber content is a primary determinant of dietary energy value of DDGS for poultry. Distillers corn oil, which is extracted from thin stillage during production of distillers grains, can also be supplemented into poultry diets as an energy-dense lipid source in place of animal fats or other vegetable-based oils. Poultry feeding practices in the United States are also evolving, including increased adoption of all vegetable-based diets and reduced use of in-feed antimicrobials. Therefore, further characterization of both the nutritional value of DDGS and its impact on gastrointestinal health will support its continued use in poultry diets.

Does ethanol production affect corn basis volatility?

PurposeSouth Dakota is ranked sixth nationally for corn and ethanol production (EP). The purpose of this paper is to investigate the relationship between corn-EP and corn basis volatility using South Dakota data.Design/methodology/approachA mixed regression modeling approach was adopted to analyze state EP data, and quarterly corn production and price data for five crop reporting regions in South Dakota (1990-2014).FindingsFrom 2004-Q4 to 2013-Q4, ethanol and corn production in South Dakota increased by 735.50 million gallons and 228.30 million bushel per year, respectively. Empirical estimates indicate that increased EP narrowed the corn basis by 6.16 cents per bushel, and increased corn basis absolute volatility by 2.25 cents. However, increased corn production widened the corn basis by 27.56 cents per bushel and decreased absolute basis volatility by 4.32 cents. On average, for this period, increased EP offset the effect of rapid corn production on average basis and basis volatility in the State of South Dakota. Empirical evidence presented clarifies how the relationship between EP and corn production variability effects the cash basis and basis volatility in local markets.Research limitations/implicationsResearch limitations include the use of statewide EP due to the lack of regional data, and the use of aggregate price data rather than local cash market data.Practical implicationsDuring normal crop production years, corn production is a predominant driver for impacting corn basis and basis volatility. In this case, EP plays a secondary role and dampens the corn production effect by narrowing the cash basis and increasing volatility. However, when a negative corn production shock occurs, then EP amplifies the effect of reduced corn production. In this case, EP strengthens market forces that are narrowing the cash basis and amplifies the market forces that are increasing the volatility of the cash basis.Social implicationsNegative corn production shocks occurring in regions where corn production and corn-based EP are dominant agricultural activities will increase basis volatility, reducing hedging effectiveness. Expansion of the ethanol blending wall in the future may exacerbate the market forces that have evolved in local cash corn markets as EP renews its expansion in major corn production regions. As a result, producers and grain elevator managers need to be aware that traditional hedging strategies may become less effective as one consequence of a renewed expansion of EP in the USA.Originality/valueThe literature on the effect of corn-EP on corn basis volatility is limited. This is the first study to apply a mixed modeling approach to the issue of how EP affected corn basis and basis volatility.

Net Energy Gain and Water Footprint of Corn Ethanol Production in Thailand

Abstract: The aims of this research are to study and compare energy efficiency or Net Energy Gain (NEG) and Water Footprint (WF) of corn-based 99.5% purified ethanol production with different kinds of raw materials for ethanol production using the Life Cycle Assessment (LCA) technique. 1 L of corn-based ethanol product was set as a functional unit. System boundary was considered from corn plantation, ethanol production, transportation, and using. For the energy analysis, the results show that corn-based ethanol production has lower energy efficiency than sugarcane, cassava, and molasses-based ethanol about 3.72, 3.48 and 1.82 times, respectively. The WF in the whole life cycle of corn-based ethanol production chain is 3.67 m3 per L ethanol, wtih the green contribution of 53.7%, the grey contribution of 43.8, and the blue contribution of 2.4%. The amount of water consumption to meet the capacity in year 2013 of bioethanol (949.1 millions L) in Thailand in scenarion 1 (72% sugarcane, 18% cassava and 10% corn) and scenario 2 (62% sugarcane, 28% cassava and 10% corn) are lower than basecase (72% sugarcane and 28% cassava) by 8.7% and 3.4%, respectively. Because corn-base ethanol production has lower WF than sugarcane and cassava-based ethanol production about 1.65 and 2.71 times, respectively.

Microbial Production of Malic Acid from Biofuel-Related Coproducts and Biomass

The dicarboxylic acid malic acid synthesized as part of the tricarboxylic acid cycle can be produced in excess by certain microorganisms. Although malic acid is produced industrially to a lesser extent than citric acid, malic acid has industrial applications in foods and pharmaceuticals as an acidulant among other uses. Only recently has the production of this organic acid from coproducts of industrial bioprocessing been investigated. It has been shown that malic acid can be synthesized by microbes from coproducts generated during biofuel production. More specifically, malic acid has been shown to be synthesized by species of the fungus Aspergillus on thin stillage, a coproduct from corn-based ethanol production, and on crude glycerol, a coproduct from biodiesel production. In addition, the fungus Ustilago trichophora has also been shown to produce malic acid from crude glycerol. With respect to bacteria, a strain of the thermophilic actinobacterium Thermobifida fusca has been shown to produce malic acid from cellulose and treated lignocellulosic biomass. An alternate method of producing malic acid is to use agricultural biomass converted to syngas or biooil as a substrate for fungal bioconversion. Production of poly(β-l-malic acid) by strains of Aureobasidium pullulans from agricultural biomass has been reported where the polymalic acid is subsequently hydrolyzed to malic acid. This review examines applications of malic acid, metabolic pathways that synthesize malic acid and microbial malic acid production from biofuel-related coproducts, lignocellulosic biomass and poly(β-l-malic acid).

How to Measure Greenhouse Gas Emissions by Fuel Type for Binary Sustainability Standards: Average or Marginal Emissions? An Example of Fertilizer Use and Corn Ethanol

This study proposed a modelling framework which addresses various issues such as decreasing marginal yield of corn with respect to fertilizer use in biofuel production and the resulting greenhouse gas emissions. Particularly, the framework considered exogenous changes including oil price development and biofuel policy through market interactions of different inputs and outputs in biofuel production. We applied the modelling framework numerically in an example of corn ethanol production in the United States to illustrate how the economics of fertilizer use could impact the GHG emissions based on both average and marginal emissions. The results show that higher oil prices increase the prices of gasoline, natural gas, ethanol, and corn, which stimulates corn-based ethanol production and increases corn yields by encouraging profit-maximizing farmers to increase their application rate of nitrogen fertilizers slightly. The effect is that, on average, GHG emissions per unit of produced corn ethanol remain almost constant if oil price increases from 60 to 120 $/barrel. However, the marginal emissions per additional unit of ethanol production increase by 2.2% or10%, depending on whether the Volumetric Ethanol Excise Tax Credit is implemented or not. More important is that the marginal emissions of corn ethanol are much higher than those of conventional gasoline. Although on average there are GHG emission savings of corn ethanol compared to conventional gasoline, the savings are negative when based on the marginal emissions of corn ethanol. An interesting implication is that the effectiveness of biofuel policies aimed at reducing GHG emissions might be questionable.

Booms, Blooms, and Doom: The Life of the Gulf of Mexico Dead Zone

Booms, Blooms, and Doom:The Life of the Gulf of Mexico Dead Zone Jack E. Davis (bio) For fourteen weeks in the winter and early spring of 2016, snow and rain kept falling on the Midwestern states. There were a few dry days in between many wet ones, but the usual long spells failed to come. Weather trackers had never seen the Midwest escape drought for such an extended period. Not surprisingly, precipitation exceeded annual averages for much of the region. In April, eight inches of rain soaked northwestern Missouri, where no more than three were normal, and in the first two weeks of the month, snowfall in northern Ohio reached up to seventeen inches above average.1 Midwestern farmers welcomed the moistening of the soil, just as long as the rain stopped before the ground turned too muddy for planting. The rain stopped. By the first of May, the majority of the corn crop was in the ground, surpassing a five-year average, and soybeans were close behind. These were the region's principal cash crops. The growing season was off to a nice start. But what was good for farmers of the Midwest was bad for sea life down in the northern Gulf of Mexico, hundreds of miles from the growing fields. In June, a two-decker headline in Mother Jones warned that the Gulf "is about to experience a 'dead zone' the size of Connecticut," nearly 6,000 square miles. Typically, the seasonal dead [End Page 156] zone kept to Delaware dimensions, its length running the front of Louisiana, reaching toward Texas in one direction, Alabama in the other, and some 40 miles into the Gulf.2 Scientists discovered the Gulf of Mexico dead zone in the 1970s, as an annual summer event. Within a few years they tracked down its principal source to chemical fertilizer runoff from the Mississippi River drainage basin, which taps forty percent of the contiguous United States, a total of thirty–one states. The area includes the Midwest and most of the High Plains, America's agricultural heartland. Corn, the biggest crop in the region and a fertilizer hog, was the principal contributor to the Gulf's woes. In the twenty–first century, with the increased production of corn-based ethanol, scientists saw a spike in fertilizer use and in the size of the dead zone. From the beginning, the ethanol connection made interesting copy for the media. Federal assistance greatly expanded the additive's presence in the domestic fuel inventory, and scientists looking for answers to reducing the dead zone, operating on federal grants in many cases, were sobered by the eclipsing power of the marketplace. But there is an important backstory here that remains adrift from the news-generating narrative. Long before ethanol's ascendency, the dead zone came to life in postwar America and of age with the baby boom generation. A defining facet in the boomer experience was the changing culinary landscape, an overall distressing development for Americans and the Gulf together. The diet of the new generation spiraled away from nutritional goodness and took a fateful turn into rivers and streams in the direction of the Gulf. Ultimately, the diminishing physical health of Americans translated into the diminishing health of their backyard sea. ________ journalists came up with the name "dead zone" in the 1980s for what scientists were abstrusely calling hypoxic coastal waters. The oxygen level in such areas, some several hundred acres and others [End Page 157] several thousand square miles, periodically drops to a level too low to support marine life. The results are mass die offs of sea creatures, especially bottom dwellers. Behind the morbidity lies an excessive infusion of nutrients. The overloading stimulates phytoplankton blooms, and, eventually, all this new minuscule life begins to die and sink to the bottom, often with other decaying organic matter. Performing its custodial role in the ecosystem, bacteria steps in to break down the dead, generating carbon dioxide as it consumes massive quantities of oxygen, leaving sea creatures to suffocate. Dead zones are worldwide. Some are natural, others the fallout of human activities. The former have been around for time immemorial. Alabama's Mobile Bay...

An Exploration of Agricultural Lands Devoted to Corn-Based Ethanol Production

ABSTRACTDebate has surrounded corn-based ethanol since its introduction as a biofuel. This debate centers on whether corn-based ethanol plays a positive or negative role with regard to energy consumption, hunger and malnutrition, environmental degradation, and economic impacts. This study aims to improve the understanding of the changes in the amount of land in the United States devoted to corn production for corn-based ethanol. Through geographical analysis using data from the U.S. Department of Agriculture National Agricultural Statistics Service, this research explores (1) the change, from 2007 to 2012, in total number of acres harvested in each county of the United States; (2) the change, from 2007 to 2012, in total number of corn acres harvested in each county of the United States; and (3) significant relationships among total acres harvested and total corn acres harvested (2007–2012) by states in the United States. This analysis of corn production can aid in a further understanding of the land allocation increases in U.S. counties and states due to rising corn-based ethanol, livestock, and human population demands. The analysis provides potential awareness to the stressors corn production has on U.S. lands and the cultivation of other crops within county and state-level regions.

Comparative study of life cycle environmental and economic impact of corn- and corn stalk-based-ethanol production

A cost-coupled life cycle environmental assessment was implemented to estimate the economic and environmental impact of corn stalk-based ethanol production. Corn-based ethanol production is used as a control group in this study. For both scenarios, the effects of respiratory inorganics, global warming, and non-renewable energy categories have important contributions to the overall environmental impact related to chemical production, coal-based energy generation, or diesel consumption for road transport stages. Corn stalk-based ethanol production is environmentally friendlier than corn-based ethanol production in the dominant categories of respiratory inorganics, global warming, non-renewable energy, carcinogens, land occupation, and terrestrial acidification/nutrification. However, producing corn stalk-based ethanol production is uneconomical because of the relatively high cost of enzymes. In addition, increasing corn stalk consumption efficiencies, decreasing stalk transport distances, and electing natural gas-fired energy-generation (e.g., electricity, steam) technologies are highly recommended for reducing adverse environment or economic effects.

Life cycle assessment of corn-based ethanol production in Argentina

The promotion of biofuels as energy for transportation in the world is mainly driven by the perspective of oil depletion, the concerns about energy security and global warming.In Argentina, the legislation has imposed the use of biofuels in blend with fossil fuels (5 to 10%) in the transport sector.The aim of this paper is to assess the environmental impact of corn-based ethanol production in the province of Santa Fe in Argentina based on the life cycle assessment methodology.The studied system includes from raw materials production to anhydrous ethanol production using dry milling technology. The system is divided into two subsystems: agricultural system and refinery system. The treatment of stillage is considered as well as the use of co-products (distiller's dried grains with solubles), but the use and/or application of the produced biofuel is not analyzed: a cradle-to-gate analysis is presented. As functional unit, 1MJ of anhydrous ethanol at biorefinery is chosen.Two life cycle impact assessment methods are selected to perform the study: Eco-indicator 99 and ReCiPe. SimaPro is the life cycle assessment software used. The influence of the perspectives on the model is analyzed by sensitivity analysis for both methods.The two selected methods identify the same relevant processes. The use of fertilizers and resources, seeds production, harvesting process, corn drying, and phosphorus fertilizers and acetamide–anillide-compounds production are the most relevant processes in agricultural system. For refinery system, corn production, supplied heat and burned natural gas result in the higher contributions. The use of distiller's dried grains with solubles has an important positive environmental impact.

Vitamin composition of new-generation corn distillers dried grains with solubles

SUMMARY Corn distillers dried grains with solubles (cDDGS) is a coproduct of the production of corn-based ethanol. Researchers have extensively studied the energy, protein, amino acid, and mineral composition of cDDGS; however, an evaluation of the vitamin content of the cDDGS has yet to be undertaken. Thus, this study was conducted to determine the vitamin composition of cDDGS. In addition, correlations between crude fat and vitamin E (α-tocopherol) of the 6 samples of cDDGS were determined. Crude fat and 8 representative vitamins [vitamin A, vitamin D, vitamin E (α-tocopherol), thiamine, riboflavin, biotin, pantothenic acid, and pyridoxine] of cDDGS samples were analyzed and the determined vitamin content was compared with the standard values of the NRC. The mean value of vitamin E (α-tocopherol) in the 6 cDDGS samples was 6.8 mg/kg. In addition, the mean values of thiamine and riboflavin in the 6 cDDGS samples were 7.7 and 2.3 mg/kg, respectively. The mean values of pyridoxine and pantothenic acid in the cDDGS samples were 3.5 and 10.9 mg/kg, respectively. On the basis of regression analysis, a positive relationship existed between crude fat and vitamin E (R = 0.6677, P = 0.1473) in the 6 samples. These findings add to the information available regarding the vitamin profile of cDDGS and will assist in decisions made on the use of cDDGS in poultry diets.

Well-to-wheels energy use and greenhouse gas emissions of ethanol from corn, sugarcane and cellulosic biomass for US use

Globally, bioethanol is the largest volume biofuel used in the transportation sector, with corn-based ethanol production occurring mostly in the US and sugarcane-based ethanol production occurring mostly in Brazil. Advances in technology and the resulting improved productivity in corn and sugarcane farming and ethanol conversion, together with biofuel policies, have contributed to the significant expansion of ethanol production in the past 20 years. These improvements have increased the energy and greenhouse gas (GHG) benefits of using bioethanol as opposed to using petroleum gasoline. This article presents results from our most recently updated simulations of energy use and GHG emissions that result from using bioethanol made from several feedstocks. The results were generated with the GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) model. In particular, based on a consistent and systematic model platform, we estimate life-cycle energy consumption and GHG emissions from using ethanol produced from five feedstocks: corn, sugarcane, corn stover, switchgrass and miscanthus. We quantitatively address the impacts of a few critical factors that affect life-cycle GHG emissions from bioethanol. Even when the highly debated land use change GHG emissions are included, changing from corn to sugarcane and then to cellulosic biomass helps to significantly increase the reductions in energy use and GHG emissions from using bioethanol. Relative to petroleum gasoline, ethanol from corn, sugarcane, corn stover, switchgrass and miscanthus can reduce life-cycle GHG emissions by 19–48%, 40–62%, 90–103%, 77–97% and 101–115%, respectively. Similar trends have been found with regard to fossil energy benefits for the five bioethanol pathways.

Separation of scleroglucan and cell biomass from Sclerotium glucanicum grown in an inexpensive,by-product based medium

Abstract: Scleroglucan is an extracellular polysaccharide produced by the fungi Sclerotium. Scleroglucan is stable over a broad range of temperatures, pH and salt concentration, thus having great potential in many diverse applications. Common media for scleroglucan production contain expensive components, such as yeast extract, that make the medium cost-ineffective for some industrial applications. Thus we developed a medium which uses C ondensed C orn S olubles (CCS), a nutrient-rich byproduct of corn-based ethanol production, to replace expensive components. Methods typically used to recover scleroglucan are also expensive, and can limit commercialization. To evaluate alternative processes for scleroglucan recovery, we prepared scleroglucan in a modified version of Wang’s medium and a CCS-glucose medium. Broth samples were initially subjected to the standard recovery method to develop a complete mass balance, and then we evaluated various treatments to improve scleroglucan recovery. These included heat treatments to lyse cells, using different alcohol precipitants, freezing or refrigerating before recovery, and diluting broth to enhance cell separation. The CCS medium produced 14.2 g/L scleroglucan, compared to 10.1 g/L in the modified Wang’s medium. Based on the standard recovery protocol, we determined that 96% of the scleroglucan was recovered from the initial centrifugation and precipitation. Washing the cell pellet with water and recentrifuging only recovered a minimal amount of scleroglucan, and thus it could be eliminated from protocol to save energy and costs. Lysing cells by boiling or autoclaving did not release more scleroglucan than un-heated samples, and we also found no statistical difference between ethanol, isopopanol, and methanol as scleroglucan precipitants. Refrigerating the broth prior to scleroglucan recovery had no significant effect, while freezing actually decreased scleroglucan recovery. Initially diluting the broth by 0.50 or 0.34 resulted in the greatest scleroglucan recovery, while higher or lower dilutions decreased recovery. The optimum protocol for scleroglucan recovery was a 0.50 dilution of broth prior to centrifugation, no washing of the cell pellet, and use of the least expensive alcohol to precipitate scleroglucan from the supernatant. Keywords: s cleroglucan, Sclerotium glucanicum , exopolysaccharide separation, condensed corn solubles DOI: 10.3965/j.issn.1934-6344.20 11 .0 1 .0 52 -0 60 Citation: Arlene Fosmer, William Gibbons . Separation of scleroglucan and cell biomass from Sclerotium glucanicum grown in an inexpensive, by-product based medium. Int J Agric & Biol Eng, 20 11 ; 4 ( 1 ): 52 <span style=font-size: 9pt; line-height: 140%; font-family:

Environmental variables controlling site suitability for corn-based ethanol production in Nebraska

Ethanol production from corn (Zea mays L.) has become a new avenue for economic vitality in the state of Nebraska. Although economic, technological and political analyses have previously been performed, this study aims to analyze a suite of environmental variables specific to corn production in Nebraska. The overall objective of this research is to better understand the spatial distribution of natural resources in Nebraska related to site selection of corn-based ethanol plants. Principal component analysis was used to determine, which environmental variables explained the majority of the variance in determining location suitability for an ethanol plant. In the first principal component, the highest loadings are irrigation requirement (0.912), growing season precipitation (0.870), rain-fed corn yield (0.840), and corn land abundance (0.735). In the second principal component, the highest loadings are potential competition for corn inputs (0.629) and irrigation restrictions (0.613). Our findings support the hypothesis that the controls related to water and land resources are playing a larger role in determining the location for ethanol plant locations than controls related to competition. This research was intended to become a foundation of methodology which could be used in other states and on other crops harvested for biofuel production. The results of this study illuminate some of the most influential environmental variables on Nebraskan ethanol plant location suitability.

The Ethanol Decade: An Expansion of U.S. Corn Production, 2000-09

The recent 9-billion-gallon increase in corn-based ethanol production, which resulted from a combination of rising gasoline prices and a suite of Federal bioenergy policies, provides evidence of how farmers altered their land-use decisions in response to increased demand for corn. As some forecasts had suggested, corn acreage increased mostly on farms that previously specialized in soybeans. Other farms, however, offset this shift by expanding soybean production. Farm-level data reveal that the simultaneous net expansion of corn and soybean acreage resulted from a reduction in cotton acreage, a shift from uncultivated hay to cropland, and the expansion of double cropping (consecutively producing two crops of either like or unlike commodities on the same land within the same year).