Science.gov

Sample records for afex-treated corn stover

  1. Cellulosic ethanol production from AFEX-treated corn stover using Saccharomyces cerevisiae 424A(LNH-ST)

    PubMed Central

    Lau, Ming W.; Dale, Bruce E.

    2009-01-01

    Current technology using corn stover (CS) as feedstock, Ammonia Fiber Expansion (AFEX) as the pretreatment technology, and Saccharomyces cerevisiae 424A(LNH-ST) as the ethanologenic strain in Separate Hydrolysis and Fermentation was able to achieve 191.5 g EtOH/kg untreated CS, at an ethanol concentration of 40.0 g/L (5.1 vol/vol%) without washing of pretreated biomass, detoxification, or nutrient supplementation. Enzymatic hydrolysis at high solids loading was identified as the primary bottleneck affecting overall ethanol yield and titer. Degradation compounds in AFEX-pretreated biomass were shown to increase metabolic yield and specific ethanol production while decreasing the cell biomass generation. Nutrients inherently present in CS and those resulting from biomass processing are sufficient to support microbial growth during fermentation. This platform offers the potential to improve the economics of cellulosic ethanol production by reducing the costs associated with raw materials, process water, and capital equipment. PMID:19164763

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

    PubMed Central

    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

  3. Hydrolysis by commercial enzyme mixtures of AFEX-treated corn fiber and isolated xylans

    SciTech Connect

    Hespell, R.B.; O`Bryan, P.J.; Bothast, R.J.; Moniruzzaman, M.

    1997-01-01

    Corn fiber is a coproduct produced during the corn wet-milling process and is similar to other high hemicellulose/cellulose-containing biomass such as grasses, straws, or bagasse, all of which represent potential fermentation feedstock for conversion into biofuels or other products. Corn fiber was subjected to ammonia-explosion (AFEX) treatment to increase degradability and then enzymatically digested with a combined mixture of commercial amylase, xylanase, and cellulose enzyme preparations. Whereas the starch and cellulose components were converted solely to glucose, oligosaccharides represented 30-40% of the xylan degradation products. This enzyme mixture also produced substantial oligosaccharides with xylans purified from corn fiber, corn germ, beech-wood, oatspelt, or wheat germ. Commercial xylan-degrading enzyme preparations containing xylanase, xylosidase, and arabinosidase activities were then used alone or in varying combinations to attempt to maximize degradation of these isolated xylans of differing chemical compositions. 25 refs., 5 tabs.

  4. Separation of Glucose and Pentose Sugars by Selective Enzyme Hydrolysis of AFEX-Treated Corn Fiber

    NASA Astrophysics Data System (ADS)

    Hanchar, Robert J.; Teymouri, Farzaneh; Nielson, Chandra D.; McCalla, Darold; Stowers, Mark D.

    A process was developed to fractionate corn fiber into glucose- and pentose-rich fractions. Corn fiber was ammonia fiber explosion treated at 90°C, using 1 g anhydrous ammonia per gram of dry biomass, 60% moisture, and 30-min residence time. Twenty four hour hydrolysis of ammonia fiber explosion-treated corn fiber with cellulase converted 83% of available glucanto-glucose. In this hydrolysis the hemicellulose was partially broken down with 81% of the xylan and 68% of the arabinan being contained in the hydrolysate after filtration to remove lignin and other insoluble material. Addition of ethanol was used to precipitate and recover the solubilized hemicellulose from the hydrolysate, followed by hydrolysis with 2% (v/v) sulfuric acid to convert the recovered xylan and arabinan to monomeric sugars. Using this method, 57% of xylose and 54% of arabinose available in corn fiber were recovered in a pentose-rich stream. The carbohydrate composition of the pentose-enriched stream was 5% glucose, 57% xylose, 27% arabinose, and 11% galactose. The carbohydrate composition of the glucose-enriched stream was 87% glucose, 5% xylose, 6% arabinose, and 1% galactose, and contained 83% of glucose available from the corn fiber.

  5. Effect of pelleting process variables on physical properties and sugar yields of ammonia fiber expansion pretreated corn stover

    SciTech Connect

    Amber N. Hoover; Jaya Shankar Tumuluru; Farzaneh Teymouri; Garold L. Gresham; Janette Moore

    2014-07-01

    Pelletization process variables including grind size (4, 6 mm), die speed (40, 50, 60 Hz), and preheating (none, 70 degrees C) were evaluated to understand their effect on pellet quality attributes and sugar yields of ammonia fiber expansion (AFEX) pretreated biomass. The bulk density of the pelletized AFEX corn stover was three to six times greater compared to untreated and AFEX-treated corn stover. Also the durability of the pelletized AFEX corn stover was >97.5% for all pelletization conditions studied except for preheated pellets. Die speed had no effect on enzymatic hydrolysis sugar yields of pellets. Pellets produced with preheating or a larger grind size (6 mm) had similar or lower sugar yields. Pellets generated with 4 mm AFEX-treated corn stover, a 60 Hz die speed, and no preheating resulted in pellets with similar or greater density, durability, and sugar yields compared to other pelletization conditions.

  6. Sustainable Corn Stover Harvest Strategies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover has been identified as an important initial source of biomass for conversion to ethanol and other biofuels. This poster presentation outlines on-going cooperative research being conducted near Ames, IA. Our university partner is responsible for developing the one-pass harvester and our I...

  7. Specific energy requirement for compacting corn stover.

    PubMed

    Mani, Sudhagar; Tabil, Lope G; Sokhansanj, Shahab

    2006-08-01

    Corn stover is a major crop residue for biomass conversion to produce chemicals and fuels. One of the problems associated with the supply of corn stover to conversion plants is the delivery of feedstock at a low cost. Corn stover has low bulk density and it is difficult to handle. In this study, chopped corn stover samples were compacted in a piston cylinder under three pressure levels (5, 10, 15 MPa) and at three moisture content levels (5%, 10%, 15% (wb)) to produce briquettes. The total energy requirement to compress and extrude briquette ranged from 12 to 30 MJ/t. The briquette density ranged from 650 to 950 kg/m3 increasing with pressure. Moisture content had also a significant effect on briquette density, durability and stability. Low moisture stover (5-10%) resulted in denser, more stable and more durable briquettes than high moisture stover (15%). PMID:16139500

  8. Multipass rotary shear comminution process to produce corn stover particles

    DOEpatents

    Dooley, James H; Lanning, David N

    2015-04-14

    A process of comminution of corn stover having a grain direction to produce a mixture of corn stover, by feeding the corn stover in a direction of travel substantially randomly to the grain direction one or more times through a counter rotating pair of intermeshing arrays of cutting discs (D) arrayed axially perpendicular to the direction of corn stover travel.

  9. Production of ethanol and furfural from corn stover

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  10. Corn stover harvest: Likely effects on soil productivity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Demand for corn stover for cattle feeding is likely to be especially high this year because of poor rainfed corn performance and because drought stressed pastures and rangeland are likely to be slow to recover in 2013 and stover will be needed to feed cows. Corn stover harvest is addressed in more d...

  11. Vertical distribution of corn stover dry mass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethanol production from biomass may reduce reliance on imported fossil fuel, increase revenue for farmers and rural communities, and reduce rates of greenhouse gas production. Corn stover and other crop biomass are viewed by the renewable energy industry as an inexpensive, "unused" source of feedsto...

  12. Metabolism of Multiple Aromatic Compounds in Corn Stover Hydrolysate by Rhodopseudomonas palustris.

    PubMed

    Austin, Samantha; Kontur, Wayne S; Ulbrich, Arne; Oshlag, J Zachary; Zhang, Weiping; Higbee, Alan; Zhang, Yaoping; Coon, Joshua J; Hodge, David B; Donohue, Timothy J; Noguera, Daniel R

    2015-07-21

    Lignocellulosic biomass hydrolysates hold great potential as a feedstock for microbial biofuel production, due to their high concentration of fermentable sugars. Present at lower concentrations are a suite of aromatic compounds that can inhibit fermentation by biofuel-producing microbes. We have developed a microbial-mediated strategy for removing these aromatic compounds, using the purple nonsulfur bacterium Rhodopseudomonas palustris. When grown photoheterotrophically in an anaerobic environment, R. palustris removes most of the aromatics from ammonia fiber expansion (AFEX) treated corn stover hydrolysate (ACSH), while leaving the sugars mostly intact. We show that R. palustris can metabolize a host of aromatic substrates in ACSH that have either been previously described as unable to support growth, such as methoxylated aromatics, and those that have not yet been tested, such as aromatic amides. Removing the aromatics from ACSH with R. palustris, allowed growth of a second microbe that could not grow in the untreated ACSH. By using defined mutants, we show that most of these aromatic compounds are metabolized by the benzoyl-CoA pathway. We also show that loss of enzymes in the benzoyl-CoA pathway prevents total degradation of the aromatics in the hydrolysate, and instead allows for biological transformation of this suite of aromatics into selected aromatic compounds potentially recoverable as an additional bioproduct. PMID:26121369

  13. A comparative study of ethanol production using dilute acid, ionic liquid and AFEX™ pretreated corn stover

    PubMed Central

    2014-01-01

    . The reason for lower ethanol yield for DA is because most of the xylose produced during the pretreatment was removed and not converted to ethanol during fermentation. Conclusions Compositional analysis of the pretreated biomass solids showed no significant change in composition for AFEX treated corn stover, while about 85% of hemicellulose was solubilized after DA pretreatment, and about 90% of lignin was removed after IL pretreatment. As expected, the optimal commercial enzyme combination was different for the solids prepared by different pretreatment technologies. Due to loss of nutrients during the pretreatment and washing steps, DA and IL pretreated hydrolysates required exogenous nutrient supplementation to ferment glucose and xylose efficiently, while AFEX pretreated hydrolysate did not require nutrient supplementation. PMID:24917886

  14. Production costs of potential corn stover harvest and storage systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover has potential as a bioenergy feedstock in North America. Here we compared production costs for various corn stover harvest (three-pass and two-pass with baling and chopping, and single-pass) and storage options (outdoor and indoor dry bales, outdoor wrapped bales, and chopped stover in b...

  15. Soil aggregation response to harvesting corn stover for bioenergy production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) stover has been identified as a primary feedstock for cellulosic bioenergy production in the U.S. Corn/Soybean Belt because of the vast area upon which the crop is grown. Developing sustainable cellulosic ethanol from corn stover residue has also been identified as a high priority...

  16. Corn stover harvest changes soil hydrology and soil aggregation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the United States, commercial-scale cellulosic-ethanol production using corn (Zea Mays L.) stover has become a reality. As the industry matures and demand for stover increases, a clear understanding of how reducing the rate of stover remaining in the field impacts soil properties is critical. Sto...

  17. Improved Multivariate Calibration Models for Corn Stover Feedstock and Dilute-Acid Pretreated Corn Stover

    SciTech Connect

    Wolfrum, E. J.; Sluiter, A. D.

    2009-01-01

    We have studied rapid calibration models to predict the composition of a variety of biomass feedstocks by correlating near-infrared (NIR) spectroscopic data to compositional data produced using traditional wet chemical analysis techniques. The rapid calibration models are developed using multivariate statistical analysis of the spectroscopic and wet chemical data. This work discusses the latest versions of the NIR calibration models for corn stover feedstock and dilute-acid pretreated corn stover. Measures of the calibration precision and uncertainty are presented. No statistically significant differences (p = 0.05) are seen between NIR calibration models built using different mathematical pretreatments. Finally, two common algorithms for building NIR calibration models are compared; no statistically significant differences (p = 0.05) are seen for the major constituents glucan, xylan, and lignin, but the algorithms did produce different predictions for total extractives. A single calibration model combining the corn stover feedstock and dilute-acid pretreated corn stover samples gave less satisfactory predictions than the separate models.

  18. Corn Stover for Bioethanol: Your New Cash Crop?

    SciTech Connect

    2001-02-01

    Biomass ethanol technology is still developing and important questions need to be answered about corn stover removal, but prospects are excellent for you to someday be able to harvest and sell a substantial portion of your stover for fuel production—without hurting your soil or main corn grain operation.

  19. Corn Stover for Bioethanol -- Your New Cash Crop?

    SciTech Connect

    Brown, H.

    2001-05-16

    Biomass ethanol technology is still developing and important questions need to be answered about corn stover removal, but prospects are excellent for you to someday be able to harvest and sell a substantial portion of your stover for fuel production--without hurting your soil or main corn grain operation.

  20. Development of sustainable corn stover harvest strategies for cellulosic ethanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The U.S. EPA identified corn (Zea mays L.) stover as “the most economical agricultural feedstock…to meet the 16 billion gallon cellulosic biofuel requirement.” They estimated that 7.8 billion gallons of ethanol would come from 82 million tons of corn stover by 2022. POET-DSM Advanced Biofuels is con...

  1. Corn stover availability for biomass conversion: situation analysis

    SciTech Connect

    Hess, J. Richard; Kenney, Kevin L.; Wright, Christopher; Perlack, Robert D; Turhollow, Jr., Anthony

    2009-08-01

    As biorefining conversion technologies become commercial, feedstock availability, supply system logistics, and biomass material attributes are emerging as major barriers to the availability of corn stover for biorefining. While systems do exist to supply corn stover as feedstock to biorefining facilities, stover material attributes affecting physical deconstruction, such as densification and post-harvest material stability, challenge the cost-effectiveness of present-day feedstock logistics systems. In addition, the material characteristics of corn stover create barriers with any supply system design in terms of equipment capacity/efficiency, dry matter loss, and capital use efficiency. However, analysis of a conventional large square bale corn stover feedstock supply system concludes that (1) where other agronomic factors are not limiting, corn stover can be accessed and supplied to a biorefinery using existing bale-based technologies, (2) technologies and new supply system designs are necessary to overcome biomass bulk density and moisture material property challenges, and (3) major opportunities to improve conventional bale biomass feedstock supply systems include improvements in equipment efficiency and capacity and reducing biomass losses in harvesting, collection, and storage. Finally, the backbone of an effective stover supply system design is the optimization of intended and minimization of unintended material property changes as the corn stover passes through the individual supply system processes from the field to the biorefinery conversion processes.

  2. Corn Stover Availability for Biomass Conversion: Situation Analysis

    SciTech Connect

    J. Richard Hess; Kevin L. Kenney; Christopher T. Wright; Robert Perlack; Anthony Turhollow

    2009-08-01

    As biorefining conversion technologies become commercial, feedstock availability, supply system logistics, and biomass material attributes are emerging as major barriers to the availability of corn stover for biorefining. While systems do exist to supply corn stover as feedstock to biorefining facilities, stover material attributes affecting physical deconstruction, such as densification and post-harvest material stability, challenge the cost-effectiveness of present-day feedstock logistics systems. In addition, the material characteristics of corn stover create barriers with any supply system design in terms of equipment capacity/efficiency, dry matter loss, and capital use efficiency. However, this study of a large, square-bale corn stover feedstock supply system concludes that (1) where other agronomic factors are not limiting, corn stover can be accessed and supplied to a biorefinery using existing bale-based technologies, (2) technologies and new supply system designs are necessary to overcome biomass bulk density and moisture material property challenges, and (3) major opportunities to improve conventional-bale biomass feedstock supply systems include improvements in equipment efficiency and capacity and reducing biomass losses in harvesting and collection and storage. Finally, the backbone of an effective stover supply system design is the optimization of intended and minimization of unintended material property changes as the corn stover passes through the individual supply system processes from the field to the biorefinery conversion processes.

  3. Soil responses to stover management in the Northern Corn Belt

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Minnesota, at the northern edge of the United States Corn Belt, is among the top corn producing states in the country. National and local interest in using corn stover for energy sparked concerns that over-harvesting biomass would degrade the highly productive soils in the region. Therefore, a study...

  4. Comparing corn stover and switchgrass biochar: characterization and sorption properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A switchgrass biochar (SB) produced by fast pyrolysis and a corn stover biochar (CSB) from a slow pyrolysis process were mechanically milled and characterized. Both of these biochars are very cost-effective and originate as residues from bioenergy production and the corn industry, respectively. Thes...

  5. Soil carbon and nitrogen dynamic after corn stover harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biofuel production from plant biomass seems to be a suitable solution to mitigate fossil fuel use and reduce greenhouse gas emissions. Corn (Zea mays) is a highly promising crop for biomass production. However, stover harvest could negatively impact soil properties. Changes in the quantity of corn r...

  6. Low-liquid pretreatment of corn stover with aqueous ammonia.

    PubMed

    Li, Xuan; Kim, Tae Hyun

    2011-04-01

    A low-liquid pretreatment method of corn stover using aqueous ammonia was studied to reduce the severity and liquid throughput associated with the pretreatment step for ethanol production. Corn stover was treated at 0.5-50.0 wt.% of ammonia loading, 1:0.2-5.0 (w/w) of solid-to-liquid ratio, 30 °C for 4-12 weeks. The effects of these conditions on the composition and enzyme digestibility of pretreated corn stover were investigated. Pretreatment of corn stover at 30°C for four weeks using 50 wt.% of ammonia loading and 1:5 solid-to-liquid ratio resulted in 55% delignification and 86.5% glucan digestibility with 15 FPU cellulase+30 CBU β-glucosidase/g-glucan. Simultaneous saccharification and fermentation of corn stover treated at 30 °C for four weeks using 50 wt.% ammonia loading and 1:2 solid-to-liquid ratio gave an ethanol yield of 73% of the theoretical maximum based on total carbohydrates (glucan+xylan) present in the untreated material. PMID:21277772

  7. Thermophysical properties of conjugated soybean oil/corn stover biocomposites.

    PubMed

    Pfister, Daniel P; Larock, Richard C

    2010-08-01

    Novel "green composites" have been prepared using a conjugated soybean oil-based resin and corn stover as a natural fiber. Corn stover is the residue remaining after grain harvest and it is estimated that approximately 75 million tons are available annually in the United States. The effect of the amount of filler, the length of the fiber, and the amount of the crosslinker on the structure and thermal and mechanical properties of the composites has been determined using Soxhlet extraction analysis, thermogravimetric analysis, dynamic mechanical analysis, and tensile testing. Increasing the amount of corn stover and decreasing the length of the fiber results in significant improvements in the mechanical properties of the composites. The Young's moduli and tensile strengths of the composites prepared range from 291 to 1398 MPa and 2.7 to 7.4 MPa, respectively. Water uptake data indicate that increasing the amount and fiber length of the corn stover results in significant increases in the absorption of water by the composites. The composites, containing 20 to 80 wt.% corn stover and a resin composed of 50 wt.% natural oil, contain 60 to 90 wt.% renewable materials and should find applications in the construction, automotive, and furniture industries. PMID:20227274

  8. Maleic acid treatment of biologically detoxified corn stover liquor.

    PubMed

    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. PMID:27262718

  9. Assessing Corn Stover Composition and Sources of Variability via NIRS

    SciTech Connect

    Templeton, D. W.; Sluiter, A. D.; Hayward, T. K.; Hames, B. R.; Thomas, S. R.

    2009-01-01

    Corn stover, the above-ground, non-grain portion of the crop, is a large, currently available source of biomass that potentially could be collected as a biofuels feedstock. Biomass conversion process economics are directly affected by the overall biochemical conversion yield, which is assumed to be proportional to the carbohydrate content of the feedstock materials used in the process. Variability in the feedstock carbohydrate levels affects the maximum theoretical biofuels yield and may influence the optimum pretreatment or saccharification conditions. The aim of this study is to assess the extent to which commercial hybrid corn stover composition varies and begin to partition the variation among genetic, environmental, or annual influences. A rapid compositional analysis method using near-infrared spectroscopy/partial least squares multivariate modeling (NIR/PLS) was used to evaluate compositional variation among 508 commercial hybrid corn stover samples collected from 47 sites in eight Corn Belt states after the 2001, 2002, and 2003 harvests. The major components of the corn stover, reported as average (standard deviation) % dry weight, whole biomass basis, were glucan 31.9 (2.0), xylan 18.9 (1.3), solubles composite 17.9 (4.1), and lignin (corrected for protein) 13.3 (1.1). We observed wide variability in the major corn stover components. Much of the variation observed in the structural components (on a whole biomass basis) is due to the large variation found in the soluble components. Analysis of variance (ANOVA) showed that the harvest year had the strongest effect on corn stover compositional variation, followed by location and then variety. The NIR/PLS rapid analysis method used here is well suited to testing large numbers of samples, as tested in this study, and will support feedstock improvement and biofuels process research.

  10. Corn stover removal affects on soil carbon in an irrigated system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover has been proposed as a possible feedstock for cellulosic ethanol production and this experiment was initiated to investigate the effects of removing corn stover on the soil resource. Corn stover has been harvested every year after grain harvest at three levels (approximately 0, 50, and 1...

  11. Flowability parameters for chopped switchgrass, wheat straw and corn stover

    SciTech Connect

    Chevanan, Nehru; Womac, A.R.; Bitra, V.S.P.; Yoder, D.C.; Sokhansanj, Shahabaddine

    2009-02-01

    A direct shear cell to measure the shear strength and flow properties of chopped switchgrass, wheat straw, and corn stover was designed, fabricated, and tested. Yield loci (r2=0.99) determined at pre-consolidation pressures of 3.80 kPa and 5.02 kPa indicated that chopped biomass followed Mohr-Coulomb failure. Normal stress significantly affected the displacement required for shear failure, as well as the friction coefficient values for all three chopped biomass types. Displacement at shear failure ranged from 30 to 80 mm, and depended on pre-consolidation pressure, normal stress, and particle size. Friction coefficient was inversely related to normal stress, and was highest for chopped corn stover. Also, chopped corn stover exhibited the highest angle of internal friction, unconfined yield strength, major consolidation strength, and cohesive strength, all of which indicated increased challenges in handling chopped corn stover. The measured angle of internal friction and cohesive strength indicated that chopped biomass cannot be handled by gravity alone. The measured angle of internal friction and cohesive strength were 43 and 0.75 kPa for chopped switchgrass; 44 and 0.49 kPa for chopped wheat straw; and 48 and 0.82 kPa for chopped corn stover. Unconfined yield strength and major consolidation strength used for characterization of bulk flow materials and design of hopper dimensions were 3.4 and 10.4 kPa for chopped switchgrass; 2.3 and 9.6 kPa for chopped wheat straw and 4.2 and 11.8 kPa for chopped corn stover. These results are useful for development of efficient handling, storage, and transportation systems for biomass in biorefineries.

  12. Current and potential U.S. Corn Stover Supplies

    SciTech Connect

    Graham, Robin Lambert; Nelson, R; Perlack, Robert D; Sheehan, J.; Wright, Lynn L

    2007-01-01

    Agricultural residues such as corn (Zea mays L.) stover are a potential feedstock for bioenergy and bio-based products that could reduceU.S. dependence on foreign oil. Collection of such residues must take into account concerns that residue removal could increase erosion, reduce crop productivity, and deplete soil carbon and nutrients. This article estimates where and how much corn stover can be collected sustainably in the USA using existing commercial equipment and estimates costs of that collection. Erosion constraints to collection were considered explicitly, and crop productivity and soil nutrient constraints were considered implicitly, by recognizing the value of residues for maintaining soil moisture and including the cost of fertilizer to replace nutrients removed. Possible soil carbon loss was not considered in the analysis. With an annual production of 196 million Mg of corn grain (about9.2 billion bushels), the USA produces 196 million Mg of stover. Under current rotation and tillage practices, about 30% of this stover could be collected for less than $33 per Mg, taking into consideration erosion and soil moisture concerns and nutrient replacement costs. Wind erosion is a major constraint to stover collection. Analysis suggests three regions of the country (central Illinois, northern Iowa/southern Minnesota, and along the Platte River in Nebraska) produce sufficient stover to support large biorefineries with one million Mg per year feedstock demands and that if farmers converted to universal no-till production of corn, then over 100 million Mg of stover could be collected annually without causing erosion to exceed the tolerable soil loss.

  13. Vertical distribution of structural components in corn stover

    SciTech Connect

    Johnson, Jane M. F.; Karlen, Douglas L.; Gresham, Garold L.; Cantrell, Keri B.; Archer, David W.; Wienhold, Brian J.; Varvel, Gary E.; Laird, David A.; Baker, John; Ochsner, Tyson E.; Novak, Jeff M.; Halvorson, Ardell D.; Arriaga, Francisco; Lightle, David T.; Hoover, Amber; Emerson, Rachel; Barbour, Nancy W.

    2014-11-17

    In the United States, corn (Zea mays L.) stover has been targeted for second generation fuel production and other bio-products. Our objective was to characterize sugar and structural composition as a function of vertical distribution of corn stover (leaves and stalk) that was sampled at physiological maturity and about three weeks later from multiple USA locations. A small subset of samples was assessed for thermochemical composition. Concentrations of lignin, glucan, and xylan were about 10% greater at grain harvest than at physiological maturity, but harvestable biomass was about 25% less due to stalk breakage. Gross heating density above the ear averaged 16.3 ± 0.40 MJ kg⁻¹, but with an alkalinity measure of 0.83 g MJ⁻¹, slagging is likely to occur during gasification. Assuming a stover harvest height of 10 cm, the estimated ethanol yield would be >2500 L ha⁻¹, but it would be only 1000 L ha⁻¹ if stover harvest was restricted to the material from above the primary ear. Vertical composition of corn stover is relatively uniform; thus, decision on cutting height may be driven by agronomic, economic and environmental considerations.

  14. Vertical distribution of structural components in corn stover

    SciTech Connect

    Jane M. F. Johnson; Douglas L. Karlen; Garold L. Gresham; Keri B. Cantrell; David W. Archer; Brian J. Wienhold; Gary E. Varvel; David A. Laird; John Baker; Tyson E. Ochsner; Jeff M. Novak; Ardell D. Halvorson; Francisco Arriaga; David T. Lightle; Amber Hoover; Rachel Emerson; Nancy W. Barbour

    2014-11-01

    In the United States, corn (Zea mays L.) stover has been targeted for second generation fuel production and other bio-products. Our objective was to characterize sugar and structural composition as a function of vertical distribution of corn stover (leaves and stalk) that was sampled at physiological maturity and about three weeks later from multiple USA locations. A small subset of samples was assessed for thermochemical composition. Concentrations of lignin, glucan, and xylan were about 10% greater at grain harvest than at physiological maturity, but harvestable biomass was about 25% less due to stalk breakage. Gross heating density above the ear averaged 16.3 ± 0.40 MJ kg?¹, but with an alkalinity measure of 0.83 g MJ?¹, slagging is likely to occur during gasification. Assuming a stover harvest height of 10 cm, the estimated ethanol yield would be >2500 L ha?¹, but it would be only 1000 L ha?¹ if stover harvest was restricted to the material from above the primary ear. Vertical composition of corn stover is relatively uniform; thus, decision on cutting height may be driven by agronomic, economic and environmental considerations.

  15. Vertical distribution of structural components in corn stover

    DOE PAGESBeta

    Johnson, Jane M. F.; Karlen, Douglas L.; Gresham, Garold L.; Cantrell, Keri B.; Archer, David W.; Wienhold, Brian J.; Varvel, Gary E.; Laird, David A.; Baker, John; Ochsner, Tyson E.; et al

    2014-11-17

    In the United States, corn (Zea mays L.) stover has been targeted for second generation fuel production and other bio-products. Our objective was to characterize sugar and structural composition as a function of vertical distribution of corn stover (leaves and stalk) that was sampled at physiological maturity and about three weeks later from multiple USA locations. A small subset of samples was assessed for thermochemical composition. Concentrations of lignin, glucan, and xylan were about 10% greater at grain harvest than at physiological maturity, but harvestable biomass was about 25% less due to stalk breakage. Gross heating density above the earmore » averaged 16.3 ± 0.40 MJ kg⁻¹, but with an alkalinity measure of 0.83 g MJ⁻¹, slagging is likely to occur during gasification. Assuming a stover harvest height of 10 cm, the estimated ethanol yield would be >2500 L ha⁻¹, but it would be only 1000 L ha⁻¹ if stover harvest was restricted to the material from above the primary ear. Vertical composition of corn stover is relatively uniform; thus, decision on cutting height may be driven by agronomic, economic and environmental considerations.« less

  16. Maleic acid treatment of biologically detoxified corn stover liquor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elimination of microbial and/or 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. Other so...

  17. Greenhouse gas fluxes in response to corn stover harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural soils play a critical role in the mitigation of increasing levels of atmospheric greenhouse gases (GHGs) such as carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4). Identifying management strategies (fertilization, tillage, irrigation) that optimize corn stover removal rates ...

  18. Sustainability of corn stover harvest strategies in Pennsylvania

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pennsylvania has a long history of harvesting corn stover after grain harvest for animal bedding and feed or as a component of mushroom compost, or as silage for dairy cattle feed. With the shallow soils and rolling topography, soil erosion and carbon losses have been minimized through extensive use...

  19. Corn stover removal reduces grain yield on marginal soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop residues such as corn stover (residue left after grain is harvested) 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 ...

  20. Can Delignification Decrease Cellulose Digestibility in Acid Pretreated Corn Stover?

    SciTech Connect

    Ishizawa, C. I.; Jeoh, T.; Adney, W. S.; Himmel, M. E.; Johnson, D. K.; Davis, M. F.

    2009-01-01

    It has previously been shown that the improved digestibility of dilute acid pretreated corn stover is at least partially due to the removal of xylan and the consequent increase in accessibility of the cellulose to cellobiohydrolase enzymes. We now report on the impact that lignin removal has on the accessibility and digestibility of dilute acid pretreated corn stover. Samples of corn stover were subjected to dilute sulfuric acid pretreatment with and without simultaneous (partial) lignin removal. In addition, some samples were completely delignified after the pretreatment step using acidified sodium chlorite. The accessibility and digestibility of the samples were tested using a fluorescence-labeled cellobiohydrolase (Trichoderma reesei Cel7A) purified from a commercial cellulase preparation. Partial delignification of corn stover during dilute acid pretreatment was shown to improve cellulose digestibility by T. reesei Cel7A; however, decreasing the lignin content below 5% (g g{sup -1}) by treatment with acidified sodium chlorite resulted in a dramatic reduction in cellulose digestibility. Importantly, this effect was found to be enhanced in samples with lower xylan contents suggesting that the near complete removal of xylan and lignin may cause aggregation of the cellulose microfibrils resulting in decreased cellulase accessibility.

  1. Development of Sustainable Corn Stover Feedstock Supply Strategies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The rising global energy demand has increased the importance of developing sustainable land management strategies. In response, the Renewable Energy Assessment Project (REAP) was begun to quantify the sustainability of harvesting corn (Zea mays L.) stover and other materials for bio-energy. REAP obj...

  2. Fuel ethanol production from alkaline peroxide pretreated corn stover

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover (CS) has the potential to serve as an abundant low-cost feedstock for production of fuel ethanol. Due to heterogeneous complexity and recalcitrance of lignocellulosic feedstocks, pretreatment is required to break the lignin seal and/or disrupt the structure of crystalline cellulose to in...

  3. Compositional Analysis of Water-Soluble Materials in Corn Stover

    SciTech Connect

    Chen, S. F.; Mowery, R. A.; Scarlata, C. J.; Chambliss, C. K.

    2007-01-01

    Corn stover is one of the leading feedstock candidates for commodity-scale biomass-to-ethanol processing. The composition of water-soluble materials in corn stover has been determined with greater than 90% mass closure in four of five representative samples. The mass percentage of water-soluble materials in tested stover samples varied from 14 to 27% on a dry weight basis. Over 30 previously unknown constituents of aqueous extracts were identified and quantified using a variety of chromatographic techniques. Monomeric sugars (primarily glucose and fructose) were found to be the predominant water-soluble components of corn stover, accounting for 30-46% of the dry weight of extractives (4-12% of the dry weight of feedstocks). Additional constituents contributing to the mass balance for extractives included various alditols (3-7%), aliphatic acids (7-21%), inorganic ions (10-18%), oligomeric sugars (4-12%), and a distribution of oligomers tentatively identified as being derived from phenolic glycosides (10-18%).

  4. Environmental Impacts of Stover Removal in the Corn Belt

    SciTech Connect

    Alicia English; Wallace E. Tyner; Juan Sesmero; Phillip Owens; David Muth

    2012-08-01

    When considering the market for biomass from corn stover resources erosion and soil quality issues are important to consider. Removal of stover can be beneficial in some areas, especially when coordinated with other conservation practices, such as vegetative barrier strips and cover crops. However, benefits are highly dependent on several factors, namely if farmers see costs and benefits associated with erosion and the tradeoffs with the removal of biomass. This paper uses results from an integrated RUSLE2/WEPS model to incorporate six different regime choices, covering management, harvest and conservation, into simple profit maximization model to show these tradeoffs.

  5. Corn stover removal impacts on soil greenhouse gas emissions in irrigated continuous corn systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Harvesting corn stover for livestock feed or for cellulosic biofuel production may impact the greenhouse gas (GHG) mitigation potential of high-yield irrigated corn. Soil emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) were measured over the 2011 growing season at two irri...

  6. Multiscale deconstruction of molecular architecture in corn stover.

    PubMed

    Inouye, Hideyo; Zhang, Yan; Yang, Lin; Venugopalan, Nagarajan; Fischetti, Robert F; Gleber, S Charlotte; Vogt, Stefan; Fowle, W; Makowski, Bryan; Tucker, Melvin; Ciesielski, Peter; Donohoe, Bryon; Matthews, James; Himmel, Michael E; Makowski, Lee

    2014-01-01

    Lignocellulosic composite in corn stover is a candidate biofuel feedstock of substantial abundance and sustainability. Its utilization is hampered by resistance of constituent cellulose fibrils to deconstruction. Here we use multi-scale studies of pretreated corn stover to elucidate the molecular mechanism of deconstruction and investigate the basis of recalcitrance. Dilute acid pretreatment has modest impact on fibrillar bundles at 0.1 micron length scales while leading to significant disorientation of individual fibrils. It disintegrates many fibrils into monomeric cellulose chains or small side-by-side aggregates. Residual crystalline fibrils lose amorphous surface material, change twist and where still cross-linked, coil around one another. Yields from enzymatic digestion are largely due to hydrolysis of individual cellulose chains and fragments generated during pretreatments. Fibrils that remain intact after pretreatment display substantial resistance to enzymatic digestion. Optimization of yield will require strategies that maximize generation of fragments and minimize preservation of intact cellulosic fibrils. PMID:24441444

  7. Multiscale deconstruction of molecular architecture in corn stover

    PubMed Central

    Inouye, Hideyo; Zhang, Yan; Yang, Lin; Venugopalan, Nagarajan; Fischetti, Robert F.; Gleber, S. Charlotte; Vogt, Stefan; Fowle, W.; Makowski, Bryan; Tucker, Melvin; Ciesielski, Peter; Donohoe, Bryon; Matthews, James; Himmel, Michael E.; Makowski, Lee

    2014-01-01

    Lignocellulosic composite in corn stover is a candidate biofuel feedstock of substantial abundance and sustainability. Its utilization is hampered by resistance of constituent cellulose fibrils to deconstruction. Here we use multi-scale studies of pretreated corn stover to elucidate the molecular mechanism of deconstruction and investigate the basis of recalcitrance. Dilute acid pretreatment has modest impact on fibrillar bundles at 0.1 micron length scales while leading to significant disorientation of individual fibrils. It disintegrates many fibrils into monomeric cellulose chains or small side-by-side aggregates. Residual crystalline fibrils lose amorphous surface material, change twist and where still cross-linked, coil around one another. Yields from enzymatic digestion are largely due to hydrolysis of individual cellulose chains and fragments generated during pretreatments. Fibrils that remain intact after pretreatment display substantial resistance to enzymatic digestion. Optimization of yield will require strategies that maximize generation of fragments and minimize preservation of intact cellulosic fibrils. PMID:24441444

  8. The effects of physical and chemical preprocessing on the flowability of corn stover

    SciTech Connect

    Crawford, Nathan C.; Nagle, Nick; Sievers, David A.; Stickel, Jonathan J.

    2015-12-20

    Continuous and reliable feeding of biomass is essential for successful biofuel production. However, the challenges associated with biomass solids handling are commonly overlooked. In this study, we examine the effects of preprocessing (particle size reduction, moisture content, chemical additives, etc.) on the flow properties of corn stover. Compressibility, flow properties (interparticle friction, cohesion, unconfined yield stress, etc.), and wall friction were examined for five corn stover samples: ground, milled (dry and wet), acid impregnated, and deacetylated. The ground corn stover was found to be the least compressible and most flowable material. The water and acid impregnated stovers had similar compressibilities. Yet, the wet corn stover was less flowable than the acid impregnated sample, which displayed a flow index equivalent to the dry, milled corn stover. The deacetylated stover, on the other hand, was the most compressible and least flowable examined material. However, all of the tested stover samples had internal friction angles >30°, which could present additional feeding and handling challenges. All of the ''wetted'' materials (water, acid, and deacetylated) displayed reduced flowabilities (excluding the acid impregnated sample), and enhanced compressibilities and wall friction angles, indicating the potential for added handling issues; which was corroborated via theoretical hopper design calculations. All of the ''wetted'' corn stovers require larger theoretical hopper outlet diameters and steeper hopper walls than the examined ''dry'' stovers.

  9. The effects of physical and chemical preprocessing on the flowability of corn stover

    DOE PAGESBeta

    Crawford, Nathan C.; Nagle, Nick; Sievers, David A.; Stickel, Jonathan J.

    2015-12-20

    Continuous and reliable feeding of biomass is essential for successful biofuel production. However, the challenges associated with biomass solids handling are commonly overlooked. In this study, we examine the effects of preprocessing (particle size reduction, moisture content, chemical additives, etc.) on the flow properties of corn stover. Compressibility, flow properties (interparticle friction, cohesion, unconfined yield stress, etc.), and wall friction were examined for five corn stover samples: ground, milled (dry and wet), acid impregnated, and deacetylated. The ground corn stover was found to be the least compressible and most flowable material. The water and acid impregnated stovers had similar compressibilities.more » Yet, the wet corn stover was less flowable than the acid impregnated sample, which displayed a flow index equivalent to the dry, milled corn stover. The deacetylated stover, on the other hand, was the most compressible and least flowable examined material. However, all of the tested stover samples had internal friction angles >30°, which could present additional feeding and handling challenges. All of the ''wetted'' materials (water, acid, and deacetylated) displayed reduced flowabilities (excluding the acid impregnated sample), and enhanced compressibilities and wall friction angles, indicating the potential for added handling issues; which was corroborated via theoretical hopper design calculations. All of the ''wetted'' corn stovers require larger theoretical hopper outlet diameters and steeper hopper walls than the examined ''dry'' stovers.« less

  10. Catalytic and atmospheric effects on microwave pyrolysis of corn stover.

    PubMed

    Huang, Yu-Fong; Kuan, Wen-Hui; Chang, Chi-Cheng; Tzou, Yu-Min

    2013-03-01

    Corn stover, which is one of the most abundant agricultural residues around the world, could be converted into valuable biofuels and bio based products by means of microwave pyrolysis. After the reaction at the microwave power level of 500W for the processing time of 30min, the reaction performance under N2 atmosphere was generally better than under CO2 atmosphere. This may be due to the better heat absorbability of CO2 molecules to reduce the heat for stover pyrolysis. Most of the metal-oxide catalysts effectively increased the maximum temperature and mass reduction ratio but lowered the calorific values of solid residues. The gas most produced was CO under N2 atmosphere but CO2 under CO2 atmosphere. Catalyst addition lowered the formation of PAHs and thus made liquid products less toxic. More liquid products and less gas products were generated when using the catalysts possibly due to the existence of the Fischer-Tropsch synthesis. PMID:23360703

  11. Quantifying and mitigating the environmental impacts of using corn stover as a biofuel feedstock

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background/Question/Methods Corn stover has been suggested as a viable biomass feedstock for bioenergy production. However, unharvested corn stover provides two important ecosystem services: it reduces soil erosion and replenishes soil carbon, both of which help maintain soil productivity. There are...

  12. Assessment of the Nutritive Value of Whole Corn Stover and Its Morphological Fractions

    PubMed Central

    Li, H. Y.; Xu, L.; Liu, W. J.; Fang, M. Q.; Wang, N.

    2014-01-01

    This study investigated the chemical composition and ruminal degradability of corn stover in three maize-planting regions in Qiqihaer, Heilongjiang Province, China. The whole stover was separated into seven morphological fractions, i.e., leaf blade, leaf sheath, stem rind, stem pith, stem node, ear husk, and corn tassel. The assessment of nutritive value of corn stover and its fractions was performed based on laboratory assays of the morphological proportions, chemical composition, and in situ degradability of dry matter (DM), neutral detergent fiber (NDF), and acid detergent fiber (ADF). The chemical composition of corn stover was significantly different from plant top to bottom (p<0.05). Among the whole corn stover and seven morphological fractions, leaf blade had the highest crude protein (CP) content and the lowest NDF and ADF contents (p<0.05), whereas stem rind had the lowest CP content and the highest ADF and acid detergent lignin (ADL) contents (p<0.05). Ear husk had significantly higher NDF content and relatively lower ADL content than other corn stover fractions. Overall, the effective degradability of DM, NDF, and ADF in rumen was the highest in leaf blade and stem pith, followed by ear husk. The results indicate that leaf blade, ear husk, and stem pith potentially have higher nutritive values than the other fractions of corn stover. This study provides reference data for high-efficiency use of corn stover in feeding ruminants. PMID:25049943

  13. CHARACTERIZATION OF SOIL AMENDED WITH THE BY-PRODUCT OF CORN STOVER FERMENTATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea Mays L.) stover is a potential biofuel; however, removing residue can increase the risk of erosion and reduce soil organic matter. After corn stover fermentation, the remaining by-product is about 70% lignin. Lignin and its breakdown and condensation products may play an essential role in ...

  14. Corn grain, stover yield, and nutrient removal validations at regional partnership sites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays, L.) stover, the aboveground material left in fields after corn grain harvest, has been selected as a major feedstock by at least four companies investing in cellulosic bioenergy. Estimates of the amount of stover that could be sustainably harvested have varied greatly depending upon ...

  15. Alkaline peroxide pretreatment of corn stover for enzymatic saccharification and ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alkaline hydrogen peroxide (AHP) pretreatment and enzymatic saccharification were evaluated for conversion of corn stover cellulose and hemicellulose to fermentable sugars. Corn stover used in this study contained 37.0±0.2% cellulose, 26.8±0.2% hemicellulose and 18.0±0.1% lignin on dry basis. Unde...

  16. Economic and environmental impacts of corn stover removal for biofuel production: A farm level case study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover is emerging as one of the major sustainable sources for cellulosic ethanol production in the U.S and promises to reduce our dependence on conventional fuels. Removal of corn stover for biomass production can provide an additional revenue generating source for farmers. However, removing c...

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

    NASA Astrophysics Data System (ADS)

    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.

  18. Anaerobic digestion of corn stovers for methane production in a novel bionic reactor.

    PubMed

    Zhang, Meixia; Zhang, Guangming; Zhang, Panyue; Fan, Shiyang; Jin, Shuguang; Wu, Dan; Fang, Wei

    2014-08-01

    To improve the biogas production from corn stovers, a new bionic reactor was designed and constructed. The bionic reactor simulated the rumen digestion of ruminants. The liquid was separated from corn stovers and refluxed into corn stovers again, which simulated the undigested particles separated from completely digested materials and fed back again for further degradation in ruminant stomach. Results showed that the bionic reactor was effective for anaerobic digestion of corn stovers. The liquid amount and its reflux showed an obvious positive correlation with biogas production. The highest biogas production rate was 21.6 ml/gVS-addedd, and the total cumulative biogas production was 256.5 ml/gVS-added. The methane content in biogas ranged from 52.2% to 63.3%. The degradation of corn stovers were greatly enhanced through simulating the animal digestion mechanisms in this bionic reactor. PMID:24923659

  19. Soil Hydraulic Properties Influenced by Corn Stover Removal from No-Till Corn in Ohio.

    SciTech Connect

    Blanco-Canqui, H.; Lal, Rattan; Post, W. M.; Izaurralde, R Cesar C.; Shipitalo, M. J.

    2007-01-01

    Corn (Zea mays L.) stover removal for biofuel production and other uses may alter soil hydraulic properties, but site-specific information needed to determine the threshold levels of removal for the U.S. Corn Belt region is limited. We quantified impacts of systematic removal of corn stover on soil hydraulic parameters after one year of stover management under no-till (NT) systems in three soils in Ohio including Rayne silt loam (fine-loamy, mixed, mesic Typic Hapludult) at Coshocton, Hoytville clay loam (fine, illitic, mesic Mollic Epiaqualfs) at Hoytville, and Celina silt loam (fine, mixed, active, mesic Aquic Hapludalfs) at South Charleston. Interrelationships among soil properties and saturated hydraulic conductivity (Ksat) predictions were also studied. Earthworm middens, Ksat, bulk density (ρb), soil-water retention (SWR), pore-size distribution, and air permeability (ka) were determined for six stover treatments including 0 (T0), 25 (T25), 50 (T50), 75 (T75), 100 (T100), and 200 (T200) % of corn stover corresponding to 0, 1.25, 2.50, 3.75, 5.00, and 10.00 Mg ha-1 of stover, respectively. Stover removal reduced the number of middens, Ksat, SWR, and ka at all sites (P<0.01). Complete stover removal reduced earthworm middens by 20-fold across sites, decreased geometric mean Ksat from 6.3 to 0.1 mm h-1 at Coshocton, 3.2 to 0.3 mm h-1 at Hoytville, and 5.8 to 0.6 mm h-1 at Charleston, and increased ρb in the 0- to 10-cm depth by about 15% relative to double stover plots. The SWR for T100 was 1.3 times higher than that for T0 at 0 to -6 kPa. The log ka for T200, T100, and T75 significantly exceeded that under T50, T25, and T0 at Coshocton and Charleston. Measured parameters were strongly correlated, and ka was a potential Ksat predictor. Stover harvesting at rates above 1.25 Mg ha-1 affects soil hydraulic properties and earthworm activity, but further monitoring is needed to ascertain the threshold levels of stover removal.Corn (Zea mays L.) stover removal for

  20. Yield response to corn stover harvest in the northern Corn Belt

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover is targeted as a potential non-food bioenergy feedstock, especially in the midwestern United States. Three parallel experiments were conducted on adjacent fields. One was managed without tillage since 1995. A second experiment was managed without tillage since 2005. The third was managed...

  1. Understanding of alkaline pretreatment parameters for corn stover enzymatic saccharification

    PubMed Central

    2013-01-01

    Background Previous research on alkaline pretreatment has mainly focused on optimization of the process parameters to improve substrate digestibility. To achieve satisfactory sugar yield, extremely high chemical loading and enzyme dosages were typically used. Relatively little attention has been paid to reduction of chemical consumption and process waste management, which has proven to be an indispensable component of the bio-refineries. To indicate alkali strength, both alkali concentration in pretreatment solution (g alkali/g pretreatment liquor or g alkali/L pretreatment liquor) and alkali loading based on biomass solids (g alkali/g dry biomass) have been widely used. The dual approaches make it difficult to compare the chemical consumption in different process scenarios while evaluating the cost effectiveness of this pretreatment technology. The current work addresses these issues through pretreatment of corn stover at various combinations of pretreatment conditions. Enzymatic hydrolysis with different enzyme blends was subsequently performed to identify the effects of pretreatment parameters on substrate digestibility as well as process operational and capital costs. Results The results showed that sodium hydroxide loading is the most dominant variable for enzymatic digestibility. To reach 70% glucan conversion while avoiding extensive degradation of hemicellulose, approximately 0.08 g NaOH/g corn stover was required. It was also concluded that alkali loading based on total solids (g NaOH/g dry biomass) governs the pretreatment efficiency. Supplementing cellulase with accessory enzymes such as α-arabinofuranosidase and β-xylosidase significantly improved the conversion of the hemicellulose by 6–17%. Conclusions The current work presents the impact of alkaline pretreatment parameters on the enzymatic hydrolysis of corn stover as well as the process operational and capital investment costs. The high chemical consumption for alkaline pretreatment technology

  2. Ash Reduction of Corn Stover by Mild Hydrothermal Preprocessing

    SciTech Connect

    M. Toufiq Reza; Rachel Emerson; M. Helal Uddin; Garold Gresham; Charles J. Coronella

    2014-04-22

    Lignocellulosic biomass such as corn stover can contain high ash content, which may act as an inhibitor in downstream conversion processes. Most of the structural ash in biomass is located in the cross-linked structure of lignin, which is mildly reactive in basic solutions. Four organic acids (formic, oxalic, tartaric, and citric) were evaluated for effectiveness in ash reduction, with limited success. Because of sodium citrate’s chelating and basic characteristics, it is effective in ash removal. More than 75 % of structural and 85 % of whole ash was removed from the biomass by treatment with 0.1 g of sodium citrate per gram of biomass at 130 °C and 2.7 bar. FTIR, fiber analysis, and chemical analyses show that cellulose and hemicellulose were unaffected by the treatment. ICP–AES showed that all inorganics measured were reduced within the biomass feedstock, except sodium due to the addition of Na through the treatment. Sodium citrate addition to the preconversion process of corn stover is an effective way to reduced physiological ash content of the feedstock without negatively impacting carbohydrate and lignin content.

  3. Evaluating corn starch and corn stover biochar as renewable filler in carboxylated styrene-butadiene rubber composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn starch, corn flour, and corn stover biochar were evaluated as potential renewable substitutes for carbon black as filler in rubber composites using carboxylated styrene-butadiene as the rubber matrix. Previous work has shown that starch-based fillers have very good reinforcement properties at t...

  4. Environmental and economic trade-offs in a watershed when using corn stover for bioenergy.

    PubMed

    Gramig, Benjamin M; Reeling, Carson J; Cibin, Raj; Chaubey, Indrajeet

    2013-02-19

    There is an abundant supply of corn stover in the United States that remains after grain is harvested which could be used to produce cellulosic biofuels mandated by the current Renewable Fuel Standard (RFS). This research integrates the Soil Water Assessment Tool (SWAT) watershed model and the DayCent biogeochemical model to investigate water quality and soil greenhouse gas flux that results when corn stover is collected at two different rates from corn-soybean and continuous corn crop rotations with and without tillage. Multiobjective watershed-scale optimizations are performed for individual pollutant-cost minimization criteria based on the economic cost of each cropping practice and (individually) the effect on nitrate, total phosphorus, sediment, or global warming potential. We compare these results with a purely economic optimization that maximizes stover production at the lowest cost without taking environmental impacts into account. We illustrate trade-offs between cost and different environmental performance criteria, assuming that nutrients contained in any stover collected must be replaced. The key finding is that stover collection using the practices modeled results in increased contributions to atmospheric greenhouse gases while reducing nitrate and total phosphorus loading to the watershed relative to the status quo without stover collection. Stover collection increases sediment loading to waterways relative to when no stover is removed for each crop rotation-tillage practice combination considered; no-till in combination with stover collection reduced sediment loading below baseline conditions without stover collection. Our results suggest that additional information is needed about (i) the level of nutrient replacement required to maintain grain yields and (ii) cost-effective management practices capable of reducing soil erosion when crop residues are removed in order to avoid contributions to climate change and water quality impairments as a result

  5. Simulated Corn Stover Removal Effects on Soil Organic Carbon and Nitrogen Dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover has traditionally been left in the field to maintain soil organic matter, protect the soil from wind and water erosion, cycle plant nutrients, provide food for soil micro- and macrofauna, and upon decomposition help stabilize soil structure. Potential interest in harvesting stover as a b...

  6. Understanding nitrogen, phosphorus, potassium and other nutrient impacts of corn stover harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) stover has been identified as an important feedstock for several uses including advanced biofuel production, enhanced animal feeds, mushroom production, and several green chemistry constituents. Harvesting stover for any of these uses will increase macronutrient (N, P, and K), sec...

  7. Corn stover nutrient removal estimates for Central Iowa, U.S.A.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the most frequently asked questions to those striving to secure sustainable corn (Zea mays L.) stover feedstock supplies for Iowa’s new bioenergy conversion facilities is “what quantity of nutrients will be removed if I harvest my stover?”. Our objective is to summarize six years of field res...

  8. Carbohydrate and nutrient composition of corn stover from three Southeastern USA locations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) stover has been identified as an important feedstock for bioenergy and bio-product production. Our objective was to quantify nutrient removal, carbohydrate composition, theoretical ethanol yield (TEY) for various stover fractions. In 2009, 2010, and 2011, whole-plant samples were ...

  9. Corn grain, stover yield and nutrient removal validations at regional partnership sites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays, L.) stover has been identified as a major feedstock for cellulosic bioenergy. This report summarizes grain and stover yield as well as N, P, and K removal at several Sun Grant Regional Partnership (SGRP) sites. National Agricultural Statistical Service (NASS) grain yields were used t...

  10. Using cover crops and animal manure to maintain or improve soil properties after corn stover removal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Establishment of no-till cover crops and application of animal manure following corn (Zea mays L.) stover removal may be potential management strategies to ameliorate any negative effects that stover removal may have on soil properties and processes. We evaluated the effects of winter rye (Secale ce...

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

    PubMed

    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. PMID:19998277

  12. Biomechanics of Wheat/Barley Straw and Corn Stover

    SciTech Connect

    Christopher T. Wright; Peter A. Pryfogle; Nathan A. Stevens; Eric D. Steffler; J. Richard Hess; Thomas H. Ulrich

    2005-03-01

    The lack of understanding of the mechanical characteristics of cellulosic feedstocks is a limiting factor in economically collecting and processing crop residues, primarily wheat and barley stems and corn stover. Several testing methods, including compression, tension, and bend have been investigated to increase our understanding of the biomechanical behavior of cellulosic feedstocks. Biomechanical data from these tests can provide required input to numerical models and help advance harvesting, handling, and processing techniques. In addition, integrating the models with the complete data set from this study can identify potential tools for manipulating the biomechanical properties of plant varieties in such a manner as to optimize their physical characteristics to produce higher value biomass and more energy efficient harvesting practices.

  13. Fuel ethanol production from corn stover under optimized dilute phosphoric acid pretreatment and enzymatic hydrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethanol is a renewable oxygenated fuel. Dilute acid pretreatment is a promising pretreatment technology for conversion of lignocellulosic biomass to fuel ethanol. Generation of fermentable sugars from corn stover involves pretreatment and enzymatic saccharification. Pretreatment is crucial as nat...

  14. Costs of Harvesting, Storing in a Large Pile, and Transporting Corn Stover in a Wet Form

    SciTech Connect

    Turhollow Jr, Anthony F; Sokhansanj, Shahabaddine

    2007-01-01

    Corn stover is potentially an attractive biomass resource, but must be stored if used to supply a biorefinery year-round. Based on experience with successfully storing water-saturated large piles of bagasse for the pulping industry, Atchison and Hettenhaus (2003) proposed that such a system can also be applied to corn stover. Regardless of the technical feasibility of this system, in this article we estimate the cost of harvesting corn stover in a single pass with corn grain, delivering the chopped biomass to a storage pile, storing the stover in a wet form in a large pile at 75% moisture in a 211,700-dry Mg facility within a radius of 24 km from the field, and transporting the stover 64 km to a biorefinery. Field-ground corn stover can be delivered to a biorefinery by rail for $55 to $61/dry Mg. Truck transport is more expensive, $71 to $77/dry Mg. To achieve a minimum cost in the system proposed by Atchison and Hettenhaus, it is necessary to field densify stover to 74 dry kg/m3, without losing combine field efficiency, have a large storage pile to spread fixed costs of storage over enough biomass, and use rail transportation. Compared to storage in an on-farm bunker silo at $60/dry Mg, there are limited circumstances in which large pile storage has a cost advantage.

  15. Pretreatment of corn stover by combining ionic liquid dissolution with alkali extraction.

    PubMed

    Geng, Xinglian; Henderson, Wesley A

    2012-01-01

    Pretreatment plays an important role in the efficient enzymatic hydrolysis of biomass into fermentable sugars for biofuels. A highly effective pretreatment method is reported for corn stover which combines mild alkali-extraction followed by ionic liquid (IL) dissolution of the polysaccharides and regeneration (recovery of the polysaccharides as solids). Air-dried, knife-milled corn stover was soaked in 1% NaOH at a moderate condition (90°C, 1 h) and then thoroughly washed with hot deionized (DI) water. The alkali extraction solublized 75% of the lignin and 37% of the hemicellulose. The corn stover fibers became softer and smoother after the alkali extraction. Unextracted and extracted corn stover samples were separately dissolved in an IL, 1-butyl-3-methylimidazolium chloride (C(4) mimCl), at 130°C for 2 h and then regenerated with DI water. The IL dissolution process did not significantly change the chemical composition of the materials, but did alter their structural features. Untreated and treated corn stover samples were hydrolyzed with commercial enzyme preparations including cellulases and hemicellulases at 50°C. The glucose yield from the corn stover sample that was both alkali-extracted and IL-dissolved was 96% in 5 h of hydrolysis. This is a highly effective methodology for minimizing the enzymatic loading for biomass hydrolysis and/or maximizing the conversion of biomass polysaccharides into sugars. PMID:21809330

  16. Alkal treatment of corn stover to improve sugar production by enzymatic hydrolysis

    SciTech Connect

    MacDonald, D.G.; Bakhshi, N.N.; Mathews, J.F.; Roychowdhury, A.; Bajpai, P.; Moo-Young, M.

    1983-08-01

    Alkali treatment of corn stover improves the availability of cellulose and hemicellulose for enzymatic attack. Treatments were carried out for 1 to 60 min at temperatures and NaOH concentrations ranging from 100 to 150 degrees C and 0 to 2%, respectively. Solubilization of the stover and sugar production by enzymatic hydrolysis (Trichoderma viride cellulase) of the solid residue and the dissolved solids were used to measure the effect of caustic treatment. At 150 degrees C and 2% NaOH concentration, 65% of the original stover was dissolved after 5 min and 52% saccharification (g sugar/g stover) of the residue and dissolved solids by enzymatic hydrolysis was achieved compared to 20% for untreated corn stover. (6 Refs.)

  17. HYGROSCOPIC MOISTURE SORPTION KINETICS MODELING OF CORN STOVER AND ITS FRACTIONS

    SciTech Connect

    Igathinathane, C.; Pordesimo, L. O.; Womac, A.R.; Sokhansanj, Shahabaddine

    2009-01-01

    Corn stover, a major crop-based lignocellulosic biomass feedstock, is required to be at an optimum moisture content for efficient bioconversion processes. Environmental conditions surrounding corn stover, as in storage facilities, affect its moisture due to hygroscopic sorption or desorption. The measurement and modeling of sorption characteristics of corn stover and its leaf, husk, and stalk fractions are useful from utilization and storage standpoints, hence investigated in this article. A benchtop low-temperature humidity chamber provided the test environments of 20 C, 30 C, and 40 C at a constant 95% relative humidity. Measured sorption characteristics with three replications for each fraction were obtained from instantaneous sample masses and initial moisture contents. Observed sorption characteristics were fitted using exponential, Page, and Peleg models. Corn stover fractions displayed a rapid initial moisture uptake followed by a slower sorption rates and eventually becoming almost asymptotic after 25 h. Sorption characteristics of all corn stover fractions were significantly different (P < 0.0001) but not the effect of temperature (P > 0.05) on these fractions. The initial 30 min of sorption was found to be critical due to peak rates of sorption from storage, handling, and processing standpoints. The Page and Peleg models had comparable performance fitting the sorption curves (R2 = 0.995), however the exponential model (R2 = 0.91) was not found suitable because of patterned residuals. The Arrhenius type relationship (P < 0.05; R2 = 0.80) explained the temperature variation of the fitted sorption model parameters. The Peleg model fitted constants, among the sorption models studied, had the best fit (R2 = 0.93) with the Arrhenius relationship. A developed method of mass proportion, involving individual corn stover fraction dry matter ratios, predicted the whole corn stover sorption characteristics from that of its individual fractions. Sorption

  18. The pretreatment of corn stover with Gloeophyllum trabeum KU-41 for enzymatic hydrolysis

    PubMed Central

    2012-01-01

    Background Pretreatment is an essential step in the enzymatic hydrolysis of biomass for bio-ethanol production. The dominant concern in this step is how to decrease the high cost of pretreatment while achieving a high sugar yield. Fungal pretreatment of biomass was previously reported to be effective, with the advantage of having a low energy requirement and requiring no application of additional chemicals. In this work, Gloeophyllum trabeum KU-41 was chosen for corn stover pretreatment through screening with 40 strains of wood-rot fungi. The objective of the current work is to find out which characteristics of corn stover pretreated with G. trabeum KU-41 determine the pretreatment method to be successful and worthwhile to apply. This will be done by determining the lignin content, structural carbohydrate, cellulose crystallinity, initial adsorption capacity of cellulase and specific surface area of pretreated corn stover. Results The content of xylan in pretreated corn stover was decreased by 43% in comparison to the untreated corn stover. The initial cellulase adsorption capacity and the specific surface area of corn stover pretreated with G. trabeum were increased by 7.0- and 2.5-fold, respectively. Also there was little increase in the cellulose crystallinity of pretreated corn stover. Conclusion G. trabeum has an efficient degradation system, and the results indicated that the conversion of cellulose to glucose increases as the accessibility of cellulose increases due to the partial removal of xylan and the structure breakage of the cell wall. This pretreatment method can be further explored as an alternative to the thermochemical pretreatment method. PMID:22559172

  19. Acetone-butanol-ethanol fermentation of corn stover: current production methods, economic viability and commercial use.

    PubMed

    Baral, Nawa R; Slutzky, Lauren; Shah, Ajay; Ezeji, Thaddeus C; Cornish, Katrina; Christy, Ann

    2016-03-01

    Biobutanol is a next-generation liquid biofuel with properties akin to those of gasoline. There is a widespread effort to commercialize biobutanol production from agricultural residues, such as corn stover, which do not compete with human and animal foods. This pursuit is backed by extensive government mandates to expand alternative energy sources. This review provides an overview of research on biobutanol production using corn stover feedstock. Structural composition, pretreatment, sugar yield (following pretreatment and hydrolysis) and generation of lignocellulose-derived microbial inhibitory compounds (LDMICs) from corn stover are discussed. The review also discusses different Clostridium species and strains employed for biobutanol production from corn stover-derived sugars with respect to solvent yields, tolerance to LDMICs and in situ solvent recovery (integrated fermentation). Further, the economics of cellulosic biobutanol production are highlighted and compared to corn starch-derived ethanol and gasoline. As discussed herein, the economic competitiveness of biobutanol production from corn stover largely depends on feedstock processing and fermentation process design. PMID:26872494

  20. Can cover crop and manure maintain or improve soil properties after stover removal from irrigated no-till corn?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Addition of cover crops and animal manure following corn (Zea mays L.) stover removal for expanded uses may mitigate negative soil property effects of stover removal. We studied the short-term (3 yr) cumulative impacts of stover removal with and without winter rye (Secale cereale L.) cover crop or a...

  1. Nitrogen, stover and tillage management affect nitrogen use efficiency in continuous corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improving nitrogen use efficiency (NUE) in corn (Zea mays L.) is critical for optimizing yield and reducing environmental impact. Stover removal in continuous corn (CC) for biofuel production, coupled with reduced-tillage systems, could alter NUE and residual soil nitrate-N. Experiments were conduct...

  2. Corn grain and stover yield prediction at R1 growth stage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) grain and stover yield estimation early in the growing season is an appealing idea. An accurate estimation of the yield of the final product could benefit farmers, as well as corn related industries. The objective of this study was to develop prediction models that could estimate ...

  3. Corn stover harvest strategy effects on grain yield and soil quality indicators

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of technologies to use cellulosic biomass as a feedstock for biofuel production was recognized as an important research focus because cellulose is a more widely-available feedstock than corn starch. Our objective was to compare various corn (Zea mays L.) stover harvest strategies to ...

  4. Enhancing biogas production of corn stover by fast pyrolysis pretreatment.

    PubMed

    Wang, Fang; Zhang, Deli; Wu, Houkai; Yi, Weiming; Fu, Peng; Li, Yongjun; Li, Zhihe

    2016-10-01

    A new thermo-chemical pretreatment by a lower temperature fast pyrolysis (LTFP) was applied to promote anaerobic digestion (AD) efficiency of corn stover (CS). The pretreatment experiment was performed by a fluidized bed pyrolysis reactor at 180, 200 and 220°C with a carrier gas flow rate of 4 and 3m(3)/h. The components characteristics, Scanning Electron Microscope (SEM) images and Crystal Intensity (CrI) of the pretreated CS were tested to explore effectiveness of the pretreatment. The results showed that the cumulative methane production at 180°C for 4 and 3m(3)/h were 199.8 and 200.3mL/g TS, respectively. As compared to the untreated CS, the LTFP pretreatment significantly (a<0.05) increased the methane production by 18.07% and 18.33%, respectively. Methane production was well fitted by the Gompertz models, and the maximum methane potential and AD efficiency was obtained at 180°C for 3m(3)/h. PMID:27420161

  5. Analyzing and Comparing Biomass Feedstock Supply Systems in China: Corn Stover and Sweet Sorghum Case Studies

    DOE PAGESBeta

    Ren, Lantian; Cafferty, Kara; Roni, Mohammad; Jacobson, Jacob; Xie, Guanghui; Ovard, Leslie; Wright, Christopher

    2015-06-11

    This paper analyzes the rural Chinese biomass supply system and models supply chain operations according to U.S. concepts of logistical unit operations: harvest and collection, storage, transportation, preprocessing, and handling and queuing. In this paper, we quantify the logistics cost of corn stover and sweet sorghum in China under different scenarios. We analyze three scenarios of corn stover logistics from northeast China and three scenarios of sweet sorghum stalks logistics from Inner Mongolia in China. The case study estimates that the logistics cost of corn stover and sweet sorghum stalk to be $52.95/dry metric ton and $52.64/dry metric ton, respectively,more » for the current labor-based biomass logistics system. However, if the feedstock logistics operation is mechanized, the cost of corn stover and sweet sorghum stalk decreases to $36.01/dry metric ton and $35.76/dry metric ton, respectively. The study also includes a sensitivity analysis to identify the cost factors that cause logistics cost variation. Results of the sensitivity analysis show that labor price has the most influence on the logistics cost of corn stover and sweet sorghum stalk, with a variation of $6 to $12/dry metric ton.« less

  6. Analyzing and Comparing Biomass Feedstock Supply Systems in China: Corn Stover and Sweet Sorghum Case Studies

    SciTech Connect

    Ren, Lantian; Cafferty, Kara; Roni, Mohammad; Jacobson, Jacob; Xie, Guanghui; Ovard, Leslie; Wright, Christopher

    2015-06-11

    This paper analyzes the rural Chinese biomass supply system and models supply chain operations according to U.S. concepts of logistical unit operations: harvest and collection, storage, transportation, preprocessing, and handling and queuing. In this paper, we quantify the logistics cost of corn stover and sweet sorghum in China under different scenarios. We analyze three scenarios of corn stover logistics from northeast China and three scenarios of sweet sorghum stalks logistics from Inner Mongolia in China. The case study estimates that the logistics cost of corn stover and sweet sorghum stalk to be $52.95/dry metric ton and $52.64/dry metric ton, respectively, for the current labor-based biomass logistics system. However, if the feedstock logistics operation is mechanized, the cost of corn stover and sweet sorghum stalk decreases to $36.01/dry metric ton and $35.76/dry metric ton, respectively. The study also includes a sensitivity analysis to identify the cost factors that cause logistics cost variation. Results of the sensitivity analysis show that labor price has the most influence on the logistics cost of corn stover and sweet sorghum stalk, with a variation of $6 to $12/dry metric ton.

  7. Analyzing and Comparing Biomass Feedstock Supply Systems in China: Corn Stover and Sweet Sorghum Case Studies

    SciTech Connect

    Mohammad S. Roni; Kara G. Cafferty; Christopher T Wright; Lantian Ren

    2015-06-01

    China has abundant biomass resources, which can be used as a potential source of bioenergy. However, China faces challenges implementing biomass as an energy source, because China has not developed the highly networked, high-volume biomass logistics systems and infrastructure. This paper analyzes the rural Chinese biomass supply system and models supply chain operations according to the U.S. concepts of logistical unit operations: harvest and collection, storage, transportation, preprocessing, and handling and queuing. In this paper, we quantify the logistics cost of corn stover and sweet sorghum under different scenarios in China. We analyze three scenarios of corn stover logistics from northeast China and three scenarios of sweet sorghum stalks logistics from Inner Mongolia in China. The case study shows that the logistics cost of corn stover and sweet sorghum stalk will be $52.95/dry metric ton and $52.64/ dry metric ton, respectively, for the current labor-based biomass logistics system. However, if the feedstock logistics operation is mechanized, the cost of corn stover and sweet sorghum stalk will be down to $36.01/ dry metric ton and $35.76/dry metric ton, respectively. The study also performed a sensitivity analysis to find the cost factors that cause logistics cost variation. A sensitivity analysis shows that labor price has the most influence on the logistics cost of corn stover and sweet sorghum stalk, causing a variation of $6 to $12/metric ton.

  8. Bio-oil and biochar production from corn cobs and stover by fast pyrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bio-oil and bio-char were produced from corn cobs and corn stover (stalks, leaves and husks) by fast pyrolysis using a pilot scale fluidized bed reactor. Yields of 60% (mass/mass) bio-oil (high heating values are ~20,000 kJ/kg, and densities > 1.0 g/mL) were realized from both corn cobs and from co...

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

    SciTech Connect

    Canter, Christina E.; Dunn, Jennifer B.; Han, Jeongwoo; Wang, Zhichao; Wang, Michael

    2015-08-18

    Here, a biorefinery may produce multiple fuels from more than one feedstock. The ability of these fuels to qualify as one of the four types of biofuels under the US Renewable Fuel Standard and to achieve a low carbon intensity score under California’s Low Carbon Fuel Standard can be strongly influenced by the approach taken to their life cycle analysis (LCA). For example, in facilities that may co-produce corn grain and corn stover ethanol, the ethanol production processes can share the combined heat and power (CHP) that is produced from the lignin and liquid residues from stover ethanol production. We examine different LCA approaches to corn grain and stover ethanol production considering different approaches to CHP treatment. In the baseline scenario, CHP meets the energy demands of stover ethanol production first, with additional heat and electricity generated sent to grain ethanol production. The resulting greenhouse gas (GHG) emissions for grain and stover ethanol are 57 and 25 g-CO2eq/MJ, respectively, corresponding to a 40 and 74% reduction compared to the GHG emissions of gasoline. We illustrate that emissions depend on allocation of burdens of CHP production and corn farming, along with the facility capacities. Co-product handling techniques can strongly influence LCA results and should therefore be transparently documented.

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

    DOE PAGESBeta

    Canter, Christina E.; Dunn, Jennifer B.; Han, Jeongwoo; Wang, Zhichao; Wang, Michael

    2015-08-18

    Here, a biorefinery may produce multiple fuels from more than one feedstock. The ability of these fuels to qualify as one of the four types of biofuels under the US Renewable Fuel Standard and to achieve a low carbon intensity score under California’s Low Carbon Fuel Standard can be strongly influenced by the approach taken to their life cycle analysis (LCA). For example, in facilities that may co-produce corn grain and corn stover ethanol, the ethanol production processes can share the combined heat and power (CHP) that is produced from the lignin and liquid residues from stover ethanol production. Wemore » examine different LCA approaches to corn grain and stover ethanol production considering different approaches to CHP treatment. In the baseline scenario, CHP meets the energy demands of stover ethanol production first, with additional heat and electricity generated sent to grain ethanol production. The resulting greenhouse gas (GHG) emissions for grain and stover ethanol are 57 and 25 g-CO2eq/MJ, respectively, corresponding to a 40 and 74% reduction compared to the GHG emissions of gasoline. We illustrate that emissions depend on allocation of burdens of CHP production and corn farming, along with the facility capacities. Co-product handling techniques can strongly influence LCA results and should therefore be transparently documented.« less

  11. Production, carbon and nitrogen in stover fractions of corn (Zea mays L.) in response to cultivar development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The contribution of genetic selection of corn to quantity and quality of stover is still poor-known. The aim of the study was to evaluate production, C and N in fractions of corn stover in response to the cultivar development. Two field experiments were conducted in the city of Rolândia (Paraná - Br...

  12. Strategies for using molecular markers to simultaneously improve corn grain yield and stover quality for ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    About 235 million metric tons of corn (Zea mays L.) stover (i.e., stalks, leaves, cobs, husks, and tassels) are left unharvested in U.S. corn fields each year. This stover represents a most abundant source of lignocellulosic substrate that can be converted to ethanol biofuel. But although today's co...

  13. Influence of corn stover harvest on soil quality assessments at multiple locations across the U.S.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover has been identified as a biofuel feedstock due to its abundance and a perception that the residues are unused trash material. However, corn stover and other plant residues play a role in maintaining soil quality (health) and enhancing productivity, thus use of this abundant material as f...

  14. Bioethanol production from corn stover using aqueous ammonia pretreatment and two-phase simultaneouos saccharification and fermentation (TPSSF)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An integrated bioconversion process was developed to convert corn-stover derived pentose and hexose to ethanol effectively. In this study, corn stover was pretreated by soaking in aqueous ammonia (SAA), which resulted in high retention of glucan (~100%) and xylan (>80%) in the solids. The pretreated...

  15. An agent-based modeling approach for determining corn stover removal rate and transboundary effects.

    PubMed

    Gan, Jianbang; Langeveld, J W A; Smith, C T

    2014-02-01

    Bioenergy production involves different agents with potentially different objectives, and an agent's decision often has transboundary impacts on other agents along the bioenergy value chain. Understanding and estimating the transboundary impacts is essential to portraying the interactions among the different agents and in the search for the optimal configuration of the bioenergy value chain. We develop an agent-based model to mimic the decision making by feedstock producers and feedstock-to-biofuel conversion plant operators and propose multipliers (i.e., ratios of economic values accruing to different segments and associated agents in the value chain) for assessing the transboundary impacts. Our approach is generic and thus applicable to a variety of bioenergy production systems at different sites and geographic scales. We apply it to the case of producing ethanol using corn stover in Iowa, USA. The results from the case study indicate that stover removal rate is site specific and varies considerably with soil type, as well as other factors, such as stover price and harvesting cost. In addition, ethanol production using corn stover in the study region would have strong positive ripple effects, with the values of multipliers varying with greenhouse gas price and national energy security premium. The relatively high multiplier values suggest that a large portion of the value associated with corn stover ethanol production would accrue to the downstream end of the value chain instead of stover producers. PMID:24276896

  16. An Agent-Based Modeling Approach for Determining Corn Stover Removal Rate and Transboundary Effects

    NASA Astrophysics Data System (ADS)

    Gan, Jianbang; Langeveld, J. W. A.; Smith, C. T.

    2014-02-01

    Bioenergy production involves different agents with potentially different objectives, and an agent's decision often has transboundary impacts on other agents along the bioenergy value chain. Understanding and estimating the transboundary impacts is essential to portraying the interactions among the different agents and in the search for the optimal configuration of the bioenergy value chain. We develop an agent-based model to mimic the decision making by feedstock producers and feedstock-to-biofuel conversion plant operators and propose multipliers (i.e., ratios of economic values accruing to different segments and associated agents in the value chain) for assessing the transboundary impacts. Our approach is generic and thus applicable to a variety of bioenergy production systems at different sites and geographic scales. We apply it to the case of producing ethanol using corn stover in Iowa, USA. The results from the case study indicate that stover removal rate is site specific and varies considerably with soil type, as well as other factors, such as stover price and harvesting cost. In addition, ethanol production using corn stover in the study region would have strong positive ripple effects, with the values of multipliers varying with greenhouse gas price and national energy security premium. The relatively high multiplier values suggest that a large portion of the value associated with corn stover ethanol production would accrue to the downstream end of the value chain instead of stover producers.

  17. Long term storage of dilute acid pretreated corn stover feedstock and ethanol fermentability evaluation.

    PubMed

    Zhang, Jian; Shao, Shuai; Bao, Jie

    2016-02-01

    This study reported a new solution of lignocellulose feedstock storage based on the distributed pretreatment concept. The dry dilute sulfuric acid pretreatment (DDAP) was conducted on corn stover feedstock, instead of ammonia fiber explosion pretreatment. Then the dry dilute acid pretreated corn stover was stored for three months during summer season with high temperature and humidity. No negative aspects were found on the physical property, composition, hydrolysis yield and ethanol fermentability of the long term stored pretreated corn stover, plus the additional merits including no chemicals recovery operation, anti-microbial contaminant environment from stronger acid and inhibitor contents, as well as the mild and slow hydrolysis in the storage. The new pretreatment method expanded the distributed pretreatment concept of feedstock storage with potential for practical application. PMID:26639616

  18. Economic Impact of Harvesting Corn Stover under Time Constraint: The Case of North Dakota

    DOE PAGESBeta

    Maung, Thein A.; Gustafson, Cole R.

    2013-01-01

    This study examines the impact of stochastic harvest field time on profit maximizing potential of corn cob/stover collection in North Dakota. Three harvest options are analyzed using mathematical programming models. Our findings show that under the first corn grain only harvest option, farmers are able to complete harvesting corn grain and achieve maximum net income in a fairly short amount of time with existing combine technology. However, under the second simultaneous corn grain and cob (one-pass) harvest option, farmers generate lower net income compared to the net income of the first option. This is due to the slowdown in combinemore » harvest capacity as a consequence of harvesting corn cobs. Under the third option of separate corn grain and stover (two-pass) harvest option, time allocation is the main challenge and our evidence shows that with limited harvest field time available, farmers find it optimal to allocate most of their time harvesting grain and then proceed to harvest and bale stover if time permits at the end of harvest season. The overall findings suggest is that it would be more economically efficient to allow a firm that is specialized in collecting biomass feedstock to participate in cob/stover harvest business.« less

  19. Bulk density and compaction behavior of knife mill chopped switchgrass,wheat straw, and corn stover

    SciTech Connect

    Chevanan, Nehru; Womac, A.R.; Bitra, V.S.P.; Igathinathane, C.; Yang, Y.T.; Miu, P.I; Sokhansanj, Shahabaddine

    2009-08-01

    Bulk density of comminuted biomass significantly increased by vibration during handling and transportation, and by normal pressure during storage. Compaction characteristics affecting the bulk density of switchgrass, wheat straw, and corn stover chopped in a knife mill at different operating conditions and using four different classifying screens were studied. Mean loose-filled bulk densities were 67.5 18.4 kg/m3 for switchgrass, 36.1 8.6 kg/m3 for wheat straw, and 52.1 10.8 kg/m3 for corn stover. Mean tapped bulk densities were 81.8 26.2 kg/m3 for switchgrass, 42.8 11.7 kg/m3 for wheat straw, and 58.9 13.4 kg/m3 for corn stover. Percentage changes in compressibility due to variation in particle size obtained from a knife mill ranged from 64.3 to 173.6 for chopped switchgrass, 22.2 51.5 for chopped wheat straw and 42.1 117.7 for chopped corn stover within the tested consolidation pressure range of 5 120 kPa. Pressure and volume relationship of chopped biomass during compression with application of normal pressure can be characterized by the Walker model and Kawakita and Ludde model. Parameter of Walker model was correlated to the compressibility with Pearson correlation coefficient greater than 0.9. Relationship between volume reduction in chopped biomass with respect to number of tappings studied using Sone s model indicated that infinite compressibility was highest for chopped switchgrass followed by chopped wheat straw and corn stover. Degree of difficulty in packing measured using the parameters of Sone s model indicated that the chopped wheat straw particles compacted very rapidly by tapping compared to chopped switchgrass and corn stover. These results are very useful for solving obstacles in handling bulk biomass supply logistics issues for a biorefinery.

  20. Conversion of Aqueous Ammonia-Treated Corn Stover to Lactic Acid by Simultaneous Saccharification and Cofermentation

    NASA Astrophysics Data System (ADS)

    Zhu, Yongming; Lee, Y. Y.; Elander, Richard T.

    Treatment of corn stover with aqueous ammonia removes most of the structural lignin, whereas retaining the majority of the carbohydrates in the solids. After treatment, both the cellulose and hemicellulose in corn stover become highly susceptible to enzymatic digestion. In this study, corn stover treated by aqueous ammonia was investigated as the substrate for lactic acid production by simultaneous saccharification and cofermentation (SSCF). A commercial cellulase (Spezyme-CP) and Lactobacillus pentosus American Type Culture Collection (ATCC) 8041 (Spanish Type Culture Collection [CECT]-4023) were used for hydrolysis and fermentation, respectively. In batch SSCF operation, the carbohydrates in the treated corn stover were converted to lactic acid with high yields, the maximum lactic acid yield reaching 92% of the stoichiometric maximum based on total fermentable carbohydrates (glucose, xylose, and arabinose). A small amount of acetic acid was also produced from pentoses through the phosphoketolase pathway. Among the major process variables for batch SSCF, enzyme loading and the amount of yeast extract were found to be the key factors affecting lactic acid production. Further tests on nutrients indicated that corn steep liquor could be substituted for yeast extract as a nitrogen source to achieve the same lactic acid yield. Fed-batch operation of the SSCF was beneficial in raising the concentration of lactic acid to a maximum value of 75.0 g/L.

  1. A Five-Year Assessment of Corn Stover Harvest in Central Iowa, USA

    SciTech Connect

    Douglas L. Karlen; Stuart J. Birell; J. Richard Hess

    2011-11-01

    Sustainable feedstock harvest strategies are needed to ensure bioenergy production does not irreversibly degrade soil resources. The objective for this study was to document corn (Zea mays L.) grain and stover fraction yields, plant nutrient removal and replacement costs, feedstock quality, soil-test changes, and soil quality indicator response to four stover harvest strategies for continuous corn and a corn-soybean [Glycine max. (L.) Merr.] rotation. The treatments included collecting (1) all standing plant material above a stubble height of 10 cm (whole plant), (2) the upper-half by height (ear shank upward), (3) the lower-half by height (from the 10 cm stubble height to just below the earshank), or (4) no removal. Collectable biomass from Treatment 2 averaged 3.9 ({+-}0.8) Mg ha{sup -1} for continuous corn (2005 through 2009), and 4.8 ({+-}0.4) Mg ha{sup -1} for the rotated corn (2005, 2007, and 2009). Compared to harvesting only the grain, collecting stover increased the average N-P-K removal by 29, 3 and 34 kg ha{sup -1} for continuous corn and 42, 3, and 34 kg ha{sup -1} for rotated corn, respectively. Harvesting the lower-half of the corn plant (Treatment 3) required two passes, resulted in frequent plugging of the combine, and provided a feedstock with low quality for conversion to biofuel. Therefore, Treatment 3 was replaced by a 'cobs-only' harvest starting in 2009. Structural sugars glucan and xylan accounted for up to 60% of the chemical composition, while galactan, arabinan, and mannose constituted less than 5% of the harvest fractions collected from 2005 through 2008. Soil-test data from samples collected after the first harvest (2005) revealed low to very low plant-available P and K levels which reduced soybean yield in 2006 after harvesting the whole-plant in 2005. Average continuous corn yields were 21% lower than rotated yields with no significant differences due to stover harvest. Rotated corn yields in 2009 showed some significant differences

  2. NIRS Prediction of Corn Stover Cell Wall Composition and Conversion Potential, and Relationships among these Traits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Implementation of a breeding program for corn stover quality traits related to cellulosic ethanol production is dependent on having a rapid and inexpensive system for phenotyping plant material. We report here on the near-infrared reflectance (NIRS) prediction equations we have developed for phenoty...

  3. Visual soil structure effects of tillage and corn stover harvest in Iowa, U.S.A.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive harvest of corn (Zea mays L.) stover for ethanol production has raised concerns regarding negative consequences on soil structure and physical quality. Visual soil structure assessment methods have the potential to help address these concerns through simple, straightforward on-farm evaluat...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  5. Pretreatment of corn stover using low-moisture anhydrous ammonia (LMAA) process

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A simple pretreatment method using anhydrous ammonia was developed to minimize water and ammonia inputs for cellulosic ethanol production, termed the low moisture anhydrous ammonia (LMAA) pretreatment. In this method, corn stover with 30 - 70 percent moisture was contacted with anhydrous ammonia in ...

  6. Improving enzymatic hydrolysis of corn stover pretreated by ethylene glycol-perchloric acid-water mixture.

    PubMed

    He, Yu-Cai; Liu, Feng; Gong, Lei; Lu, Ting; Ding, Yun; Zhang, Dan-Ping; Qing, Qing; Zhang, Yue

    2015-02-01

    To improve the enzymatic saccharification of lignocellulosic biomass, a mixture of ethylene glycol-HClO4-water (88.8:1.2:10, w/w/w) was used for pretreating corn stover in this study. After the optimization in oil-bath system, the optimum pretreatment temperature and time were 130 °C and 30 min, respectively. After the saccharification of 10 g/L pretreated corn stover for 48 h, the saccharification rate was obtained in the yield of 77.4 %. To decrease pretreatment temperature and shorten pretreatment time, ethylene glycol-HClO4-water (88.8:1.2:10, w/w/w) media under microwave irradiation was employed to pretreat corn stover effectively at 100 °C and 200 W for 5 min. Finally, the recovered hydrolyzates containing glucose obtained from the enzymatic hydrolysis of pretreated corn stovers could be fermented into ethanol efficiently. These results would be helpful for developing a cost-effective pretreatment combined with enzymatic saccharification of cellulosic materials for the production of lignocellulosic ethanol. PMID:25384544

  7. Corn stover management effects on soil organic carbon contents from several U.S. locations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover is anticipated to be a major bioenergy feedstock, which is dependent upon high quality soil. Thus, the soil resource provides the foundation for building a sustainable biofuel economy. As the foundation, this resource must be safeguarded from overzealous residue harvest, which can exacer...

  8. Monitoring soil quality to assess the sustainability of harvesting corn stover

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Harvesting feedstock for advanced biofuel production must not degrade soil, water, or air resources. Our objective of this report is to provide an overview of field research being conducted in six states to quantify effects of harvesting corn (Zea mays L.) stover as a potential bioenergy feedstock. ...

  9. Ammonia, total reduced sulfides, and greenhouse gases of pine chip and corn stover bedding packs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bedding materials may affect air quality in livestock facilities. The objective of this study was to compare headspace concentrations of ammonia (NH3), total reduced sulfides (TRS), carbon dioxide (CO2),methane (CH4), and nitrous oxide (N2O) when pine wood chips and corn stover were mixed in various...

  10. Vertical distribution of corn stover dry mass grown at several U.S. locations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover is a likely non-food agricultural feedstock for production of renewable liquid fuels, biopower and other bioproducts. Crop residues serve multiple soil functions such as erosion control and carbon and nutrient cycling. The Revised Universal Soil Loss Equation version 2 (RUSLE2) and the W...

  11. Nutrient removal as a function of corn stover cutting height and cob harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One-pass harvest equipment has been developed to collect corn (Zea mays L.) grain, stover, and cobs: three plant components that can be used as bioenergy feedstock. Nutrients removed in these feedstocks have soil fertility implications and affect feedstock quality. The study objectives were to quant...

  12. PRETREATMENT AND FRACTIONATION OF CORN STOVER BY AMMONIA RECYCLE PERCOLATION PROCESS. (R831645)

    EPA Science Inventory

    Corn stover was pretreated with aqueous ammonia in a flow-through column reactor,
    a process termed as Ammonia Recycle Percolation (ARP). The aqueous ammonia causes
    swelling and efficient delignification of biomass at high temperatures. The ARP
    process solubilizes abou...

  13. Antimicrobial and antioxidant activities of lignin from residue of corn stover to ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To improve the economic viability of the biofuel production from biomass resource, a value-added lignin byproduct from this process is increasingly interested. Antioxidant and antimicrobial activities of lignin extracted from residue of corn stover to ethanol production were investigated. The lignin...

  14. Enhancement of xylose utilization from corn stover by a recombinant bacterium for ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of substrate-selective inoculum prepared by growing on glucose, xylose, arabinose, GXA (glucose, xylose, arabinose, 1:1:1) and corn stover hydrolyzate (dilute acid pretreated and enzymatically hydrolyzed, CSH) on ethanol production from CSH by a mixed sugar utilizing recombinant Escherichia ...

  15. Drought effects on composition and yield for corn stover, mixed grasses, and Miscanthus as bioenergy feedstocks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drought conditions in 2012 were some of the most severe in recent history. The purpose of this study was to examine the impact of drought on quality, quantity, and theoretical ethanol yield (TEY) of three bioenergy feedstocks, corn stover, mixed perennial grasses from Conservation Reserve Program de...

  16. Effect of treatment and cultivar on the ensiling of corn stover

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nine cultivars of corn stover selected for ethanol potential were harvested (34 to 40% dry matter) and each ensiled with six treatments: untreated, lactic acid bacteria, cell-wall degrading enzymes, sulfuric acid, bacteria-enzyme combination and enzyme-acid combination. Ensiling was carried out in v...

  17. Corn stover management effects on soil organic carbon contents from several U.S. locations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover is anticipated to be a major bioenergy feedstock, which is dependent upon high quality soil. Thus, the soil resource provides the foundation for building a sustainable biofuel economy. As a bioenergy foundation, this resource must be safeguarded from overzealous residue harvest, which ca...

  18. Using DAYCENT to model the soil impacts of harvesting corn stover for bioenergy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Minimizing GHG emissions and avoiding soil C depletion associated with feedstock production is a key concern with the development of corn stover for biofuel, in order to prevent reductions in soil fertility and negative climate impacts from residue removal. While experimental data are valuable to un...

  19. Corn stover harvest strategy effects on grain yield and soil quality indicators

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of technologies to use cellulosic biomass as a feedstock for biofuels was recognized as an important research challenge because cellulose is available from sources that do not directly compete with food and feed production. One result was that corn (Zea mays L.) stover, the abovegrou...

  20. Multi-location corn stover harvest effects on crop yields and nutrient removal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays, L.) stover was identified as an important feedstock for cellulosic bioenergy production because of the extensive area upon which the crop is already grown. Our objective is to summarize more than 200 site-years of field research conducted across the U.S.A. to determine quantities and...

  1. DEVELOPING AN ASSAY TO DETERMINE BIOAVAILABILITY OF LIGNOCELLULOSE IN CORN STOVER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lignocellulose is said to be the most abundant compound on earth and is an excellent renewable feedstock for the production of ethanol as an alternative fuel source. Corn stover is made of lignocellulose and may prove to be an essentially free renewable energy resource. The goal of this research i...

  2. Optimization of dilute sulfuric acid pretreatment and enzymatic saccharification of corn stover for efficient ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dilute acid pretreatment is a promising pretreatment technology for conversion of lignocellulosic biomass to fuel ethanol. Corn stover (supplied by a local farmer) used in this study contained 37.0±0.4% cellulose, 31.3±0.6% hemicelluloses, and 17.8±0.2% lignin. Generation of fermentable sugars from ...

  3. Cellulosic ethanol fermentation using Saccharomyces cerevisiae seeds cultured by pretreated corn stover material.

    PubMed

    Qureshi, Abdul Sattar; Zhang, Jian; Bao, Jie

    2015-03-01

    Utilization of lignocellulose materials to replace the pure glucose for preparation of the fermenting yeast seeds could reduce the cost of ethanol fermentation, because a large quantity of glucose is saved in the large-scale seed fermentor series. In this study, Saccharomyces cerevisiae DQ1 was cultured using the freshly pretreated corn stover material as the carbon source, and then the culture broth was used as the inoculation seeds after a series of seed transfer and inoculated into the ethanol production fermentor. The results show that the yeast cell growth and ethanol fermentation performance have essentially no difference when the yeast seeds were cultured by glucose, the corn stover hydrolysate liquid, and the pretreated corn stover solids as carbon sources, respectively. Approximately 22% of the yeast cell culture cost was saved, and the process flow sheet in industrial scale plants was simplified by using the pretreated corn stover for seed culture. The results provided a practical method for materials and operational cost reduction for cellulosic ethanol production. PMID:25604953

  4. Studies of Corn Stover Decomposition Using the Litter Bag Technique

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Decomposition rates of residue from three genetically-modified corn hybrids expressing one or more Bt endotoxins were compared to that of residue from a near isogenic, unmodified hybrid. The corn hybrids were (i) DKC60-16 (Yieldguard Corn Borer), (ii) DKC60-12 (Yieldguard Corn Rootworm), (iii) DKC60...

  5. 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

    SciTech Connect

    Mani, Sudhagar; Sokhansanj, Shahabaddine; Togore, Sam; Turhollow Jr, Anthony F

    2010-03-01

    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 dam3). 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.

  6. Effect of pelleting on the recalcitrance and bioconversion of dilute-acid pretreated corn stover

    SciTech Connect

    Allison E Ray; Amber Hoover; Gary Gresham

    2012-07-01

    Background: Knowledge regarding the performance of densified biomass in biochemical processes is limited. The effects of densification on biochemical conversion are explored here. Methods: Pelleted corn stover samples were generated from bales that were milled to 6.35 mm. Low-solids acid pretreatment and simultaneous saccharification and fermentation were performed to evaluate pretreatment efficacy and ethanol yields achieved for pelleted and ground stover (6.35 mm and 2 mm) samples. Both pelleted and 6.35-mm ground stover were evaluated using a ZipperClave® reactor under high-solids, process-relevant conditions for multiple pretreatment severities (Ro), followed by enzymatic hydrolysis of the washed, pretreated solids. Results: Monomeric xylose yields were significantly higher for pellets (approximately 60%) than for ground formats (approximately 38%). Pellets achieved approximately 84% of theoretical ethanol yield (TEY); ground stover formats had similar profiles, reaching approximately 68% TEY. Pelleting corn stover was not detrimental to pretreatment efficacy for both low- and high-solids conditions, and even enhanced ethanol yields.

  7. Corn Stover to Sustain Organic Carbon Further Constrains Biomass Supply

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustainable aboveground crop biomass harvest estimates for cellulosic ethanol production, to date, have been limited by the need for stover or residue to control erosion. Recently, estimates of the amount of crop biomass needed to maintain soil carbon, which is responsible for favorable soil propert...

  8. High titer gluconic acid fermentation by Aspergillus niger from dry dilute acid pretreated corn stover without detoxification.

    PubMed

    Zhang, Hongsen; Zhang, Jian; Bao, Jie

    2016-03-01

    This study reported a high titer gluconic acid fermentation using dry dilute acid pretreated corn stover (DDAP) hydrolysate without detoxification. The selected fermenting strain Aspergillus niger SIIM M276 was capable of inhibitor degradation thus no detoxification on pretreated corn stover was required. Parameters of gluconic acid fermentation in corn stover hydrolysate were optimized in flasks and in fermentors to achieve 76.67 g/L gluconic acid with overall yield of 94.91%. The sodium gluconate obtained from corn stover was used as additive for extending setting time of cement mortar and similar function was obtained with starch based sodium gluconate. This study provided the first high titer gluconic acid production from lignocellulosic feedstock with potential of industrial applications. PMID:26724553

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

    SciTech Connect

    Powers, Susan E.

    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.

  10. Evaluation of storage methods for the conversion of corn stover biomass to sugars based on steam explosion pretreatment.

    PubMed

    Liu, Zhi-Hua; Qin, Lei; Jin, Ming-Jie; Pang, Feng; Li, Bing-Zhi; Kang, Yong; Dale, Bruce E; Yuan, Ying-Jin

    2013-03-01

    Effects of dry and wet storage methods without or with shredding on the conversion of corn stover biomass were investigated using steam explosion pretreatment and enzymatic hydrolysis. Sugar conversions and yields for wet stored biomass were obviously higher than those for dry stored biomass. Shredding reduced sugar conversions compared with non-shredding, but increased sugar yields. Glucan conversion and glucose yield for non-shredded wet stored biomass reached 91.5% and 87.6% after 3-month storage, respectively. Data of micro-structure and crystallinity of biomass indicated that corn stover biomass maintained the flexible and porous structure after wet storage, and hence led to the high permeability of corn stover biomass and the high efficiency of pretreatment and hydrolysis. Therefore, the wet storage methods would be desirable for the conversion of corn stover biomass to fermentable sugars based on steam explosion pretreatment and enzymatic hydrolysis. PMID:23395737

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

    SciTech Connect

    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.

  12. Soil nutrient budgets following projected corn stover harvest for biofuel production in the conterminous United States

    USGS Publications Warehouse

    Tan, Zhengxi; Liu, Shuguang

    2015-01-01

    Increasing demand for food and biofuel feedstocks may substantially affect soil nutrient budgets, especially in the United States where there is great potential for corn (Zea mays L) stover as a biofuel feedstock. This study was designed to evaluate impacts of projected stover harvest scenarios on budgets of soil nitrogen (N), phosphorus (P), and potassium (K) currently and in the future across the conterminous United States. The required and removed N, P, and K amounts under each scenario were estimated on the basis of both their average contents in grain and stover and from an empirical model. Our analyses indicate a small depletion of soil N (−4 ± 35 kg ha−1) and K (−6 ± 36 kg ha−1) and a moderate surplus of P (37 ± 21 kg ha−1) currently on the national average, but with a noticeable variation from state to state. After harvesting both grain and projected stover, the deficits of soil N, P, and K were estimated at 114–127, 26–27, and 36–53 kg ha−1 yr−1, respectively, in 2006–2010; 131–173, 29–32, and 41–96 kg ha−1 yr−1, respectively, in 2020; and 161–207, 35–39, and 51–111 kg ha−1 yr−1, respectively, in 2050. This study indicates that the harvestable stover amount derived from the minimum stover requirement for maintaining soil organic carbon level scenarios under current fertilization rates can be sustainable for soil nutrient supply and corn production at present, but the deficit of P and K at the national scale would become larger in the future.

  13. Handling of co-products in life cycle analysis in an evolving co-product market: A case study with corn stover removal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover (cobs and residue) is an important part of the life cycle of corn, either as fuel or as animal feed, but most life cycle analysis (LCA) models treat them separately from starch ethanol. This paper compares four stover and corn grain based ethanol pathways to show how the greenhouse gas (...

  14. Promoting anaerobic biogasification of corn stover through biological pretreatment by liquid fraction of digestate (LFD).

    PubMed

    Hu, Yun; Pang, Yunzhi; Yuan, Hairong; Zou, Dexun; Liu, Yanping; Zhu, Baoning; Chufo, Wachemo Akiber; Jaffar, Muhammad; Li, Xiujin

    2015-01-01

    A new biological pretreatment method by using liquid fraction of digestate (LFD) was advanced for promoting anaerobic biogasification efficiency of corn stover. 17.6% TS content and ambient temperature was appropriate for pretreatment. The results showed that C/N ratio decreased to about 30, while total lignin, cellulose, and hemicellulose (LCH) contents were reduced by 8.1-19.4% after pretreatment. 3-days pretreatment was considered to be optimal, resulting in 70.4% more biogas production, 66.3% more biomethane yield and 41.7% shorter technical digestion time compared with the untreated stover. The reductions on VS, cellulose, and hemicellulose were increased by 22.1-35.9%, 22.3-35.4%, and 19.8-27.2% for LFD-treated stovers. The promoted anaerobic biogasification efficiency was mainly attributed to the improved biodegradability due to the pre-decomposition role of the bacteria in LFD. The method proved to be an efficient and low cost approach for producing bioenergy from corn stover, meanwhile, reducing LFD discharge and minimizing its potential pollution. PMID:25459818

  15. Modeled Impacts of Cover Crops and Vegetative Barriers on Corn Stover Availability and Soil Quality

    SciTech Connect

    Ian J. Bonner; David J. Muth Jr.; Joshua B. Koch; Douglas L. Karlen

    2014-06-01

    Environmentally benign, economically viable, and socially acceptable agronomic strategies are needed to launch a sustainable lignocellulosic biofuel industry. Our objective was to demonstrate a landscape planning process that can ensure adequate supplies of corn (Zea mays L.) stover feedstock while protecting and improving soil quality. The Landscape Environmental Assessment Framework (LEAF) was used to develop land use strategies that were then scaled up for five U.S. Corn Belt states (Nebraska, Iowa, Illinois, Indiana, and Minnesota) to illustrate the impact that could be achieved. Our results show an annual sustainable stover supply of 194 million Mg without exceeding soil erosion T values or depleting soil organic carbon [i.e., soil conditioning index (SCI)?>?0] when no-till, winter cover crop, and vegetative barriers were incorporated into the landscape. A second, more rigorous conservation target was set to enhance soil quality while sustainably harvesting stover. By requiring erosion to be <1/2 T and the SCI-organic matter (OM) subfactor to be >?0, the annual sustainable quantity of harvestable stover dropped to148 million Mg. Examining removal rates by state and soil resource showed that soil capability class and slope generally determined the effectiveness of the three conservation practices and the resulting sustainable harvest rate. This emphasizes that sustainable biomass harvest must be based on subfield management decisions to ensure soil resources are conserved or enhanced, while providing sufficient biomass feedstock to support the economic growth of bioenergy enterprises.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Comparison of Ultrasonic and CO2 Laser Pretreatment Methods on Enzyme Digestibility of Corn Stover

    PubMed Central

    Tian, Shuang-Qi; Wang, Zhen-Yu; Fan, Zi-Luan; Zuo, Li-Li

    2012-01-01

    To decrease the cost of bioethanol production, biomass recalcitrance needs to be overcome so that the conversion of biomass to bioethanol becomes more efficient. CO2 laser irradiation can disrupt the lignocellulosic physical structure and reduce the average size of fiber. Analyses with Fourier transform infrared spectroscopy, specific surface area, and the microstructure of corn stover were used to elucidate the enhancement mechanism of the pretreatment process by CO2 laser irradiation. The present work demonstrated that the CO2 laser had potential to enhance the bioconversion efficiency of lignocellulosic waste to renewable bioethanol. The saccharification rate of the CO2 laser pretreatment was significantly higher than ultrasonic pretreatment, and reached 27.75% which was 1.34-fold of that of ultrasonic pretreatment. The results showed the impact of CO2 laser pretreatment on corn stover to be more effective than ultrasonic pretreatment. PMID:22605970

  18. Comparison of ultrasonic and CO₂laser pretreatment methods on enzyme digestibility of corn stover.

    PubMed

    Tian, Shuang-Qi; Wang, Zhen-Yu; Fan, Zi-Luan; Zuo, Li-Li

    2012-01-01

    To decrease the cost of bioethanol production, biomass recalcitrance needs to be overcome so that the conversion of biomass to bioethanol becomes more efficient. CO(2) laser irradiation can disrupt the lignocellulosic physical structure and reduce the average size of fiber. Analyses with Fourier transform infrared spectroscopy, specific surface area, and the microstructure of corn stover were used to elucidate the enhancement mechanism of the pretreatment process by CO(2) laser irradiation. The present work demonstrated that the CO(2) laser had potential to enhance the bioconversion efficiency of lignocellulosic waste to renewable bioethanol. The saccharification rate of the CO(2) laser pretreatment was significantly higher than ultrasonic pretreatment, and reached 27.75% which was 1.34-fold of that of ultrasonic pretreatment. The results showed the impact of CO(2) laser pretreatment on corn stover to be more effective than ultrasonic pretreatment. PMID:22605970

  19. Impact of enzymatic pretreatment on corn stover degradation and biogas production.

    PubMed

    Schroyen, Michel; Vervaeren, Han; Van Hulle, Stijn W H; Raes, Katleen

    2014-12-01

    Corn stover is an agricultural residue consisting of lignocellulose, cellulose and hemicellulose polymers, sheeted in a lignin barrier. Corn stover can be used as feedstock for biogas production. Previous studies have shown biological pretreatment of lignocellulose materials can increase digestibility of the substrate improving hydrolysis, the rate-limiting step in biogas production. The impact of pretreating with different enzymes (laccase, manganese peroxidase and versatile peroxidase) and different incubation times, (0, 6 and 24 h) was studied. The effect on the matrix and biomethane production was determined. Pretreatments did not yield high concentrations of phenolic compounds, inhibitors of biogas production. The laccase enzyme showed an increase in biomethane production of 25% after 24 h of incubation. Pretreatment with peroxidase enzymes increased biomethane production with 17% after 6 h of incubation. As such it can be concluded that by introducing the different enzymes at different stages during pretreatment an increased biomethane production can be obtained. PMID:25285760

  20. Effects of laccase on lignin depolymerization and enzymatic hydrolysis of ensiled corn stover.

    PubMed

    Chen, Qin; Marshall, Megan N; Geib, Scott M; Tien, Ming; Richard, Tom L

    2012-08-01

    The aim of this study was to explore the synergies of laccase, a ligninolytic enzyme, with cellulose and hemicellulase amendments on ensiled corn stover. Molecular signals of lignin decomposition were observed by tetramethylammonium hydroxide thermochemolysis and gas chromatography-mass spectroscopy (TMAH-GC-MS) analysis. The significant findings suggest that ensilage might provide a platform for biological pretreatment. By partially hydrolyzing cellulose and hemicellulose into soluble sugars, ensilage facilitates laccase penetration into the lignocellulose complex to enhance lignin degradation. Downstream cellulose hydrolysis was improved 7% with increasing laccase loading rate. These results demonstrate the potential of enzymes, either directly amended or expressed by microbes during ensilage, to maximize utilization of corn stover for cellulosic biofuels and other downstream fermentations. PMID:22613895

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

    PubMed

    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. PMID:26341009

  2. Three-stage enzymatic hydrolysis of steam-exploded corn stover at high substrate concentration.

    PubMed

    Yang, Jing; Zhang, Xiaoping; Yong, Qiang; Yu, Shiyuan

    2011-04-01

    The feasibility of three-stage hydrolysis of steam-exploded corn stover at high-substrate concentration was investigated. When substrate concentration was 30% and enzyme loading was 15-30 FPU/g cellulose, three-stage (9+9+12 h) hydrolysis could reach a hydrolysis yield of 59.9-81.4% in 30 h. Compared with one-stage hydrolysis for 72 h, an increase of 34-37% in hydrolysis yield could be achieved. When steam-exploded corn stover was used as the substrate for enzyme synthesis and hydrolysis was conducted at a substrate concentration of 25% with an enzyme loading of 20 FPU/g cellulose, a hydrolysis yield of 85.1% was obtained, 19% higher than that the commercial cellulase could reach under the same conditions. The removal of end products was suggested to improve the adsorption of cellulase on the substrate and enhance the productivity of enzymatic hydrolysis. PMID:21300538

  3. Impact of Corn Stover Composition on Hemicellulose Conversion during Dilute Acid Pretreatment and Enzymatic Cellulose Digestibility of the Pretreated Solids

    SciTech Connect

    Weiss, N. D.; Farmer, J. D.; Schell, D. J.

    2010-01-01

    This study assessed the impact of corn stover compositional variability on xylose conversion yields during dilute acid pretreatment and on enzymatic cellulose digestibility of the resulting pretreated solids. Seven compositionally-different stovers obtained from various locations throughout the United States were pretreated at three different conditions in triplicate in a pilot-scale continuous reactor. At the same pretreatment severity, a 2-fold increase in monomeric xylose yield and a 1.5-fold increase in enzymatic cellulose digestibility from their lowest values were found. Similar results were observed at the other pretreatment conditions. It was found that xylose conversion yields decreased with increasing acid neutralization capacity or soil content of the corn stover. Xylose yields also increased with increasing xylan content. No other significant correlations between corn stover's component concentrations and conversion yields were found.

  4. Speciation of sulfur in biochar produced from pyrolysis and gasification of oak and corn stover.

    PubMed

    Cheah, Singfoong; Malone, Shealyn C; Feik, Calvin J

    2014-01-01

    The effects of feedstock type and biomass conversion conditions on the speciation of sulfur in biochars are not well-known. In this study, the sulfur content and speciation in biochars generated from pyrolysis and gasification of oak and corn stover were determined. We found the primary determinant of the total sulfur content of biomass to be the feedstock from which the biochar is generated, with oak and corn stover biochars containing 160 and 600-800 ppm sulfur, respectively. In contrast, for sulfur speciation, we found the primary determinant to be the temperature combined with the thermochemical conversion method. The speciation of sulfur in biochars was determined using X-ray absorption near-edge structure (XANES), ASTM method D2492, and scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS). Biochars produced under pyrolysis conditions at 500-600 °C contain sulfate, organosulfur, and sulfide. In some cases, the sulfate contents are up to 77-100%. Biochars produced in gasification conditions at 850 °C contain 73-100% organosulfur. The increase of the organosulfur content as the temperature of biochar production increases suggests a similar sulfur transformation mechanism as that in coal, where inorganic sulfur reacts with hydrocarbon and/or H2 to form organosulfur when the coal is heated. EDS mapping of a biochar produced from corn stover pyrolysis shows individual sulfur-containing mineral particles in addition to the sulfur that is distributed throughout the organic matrix. PMID:25003702

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

    PubMed

    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. PMID:25947618

  6. Mesophilic anaerobic co-digestion of cattle manure and corn stover with biological and chemical pretreatment.

    PubMed

    Wei, Yufang; Li, Xiujin; Yu, Liang; Zou, Dexun; Yuan, Hairong

    2015-12-01

    Biological and chemical pretreatment methods using liquid fraction of digestate (LFD), ammonia solution (AS), and NaOH were compared in the process of mesophilic anaerobic co-digestion of cattle manure and corn stover. The results showed that LFD pretreatment could achieve the same effect as the chemical pretreatment (AS, NaOH) at the performance of anaerobic digestion (AD). Compared with the untreated corn stover, the cumulative biomethane production (CBP) and the volatile solid (VS) removal rate of three pretreatment methods were increased by 25.40-30.12% and 14.48-16.84%, respectively, in the co-digestion of cattle manure and corn stover. T80 was 20-37.14% shorter than that of the control test (35 ± 1 days). LFD pretreatment not only achieved the same effect as chemical pretreatment, but also reduced T80 and improved buffer capacity of anaerobic digestion system. Therefore, this study provides meaningful insight for exploring efficient pretreatment strategy to stabilize and enhance AD performance for practical application. PMID:26409855

  7. Pretreatment of corn stover for sugar production with switchgrass-derived black liquor.

    PubMed

    Xu, Jiele; Zhang, Ximing; Cheng, Jay J

    2012-05-01

    To improve the cost-effectiveness of biomass-to-sugar conversion, sodium hydroxide (NaOH) pretreatment of switchgrass was carried out at 21°C using previously determined optimum conditions (2% NaOH (w/v), 6h), and the spent alkaline liquid (black liquor) was collected and used for pretreatment of corn stover, a feedstock exhibiting a higher susceptibility to NaOH attack, for improved enzymatic hydrolysis at a reduced cost. The results showed that, because of the high pH and the appreciable amount of carbohydrates in the black liquor, sugar production during enzymatic hydrolysis of corn stover pretreated with black liquor was comparable to that of biomass pretreated with 1% NaOH. After black liquor pretreatment at the best residence time (24h), the total reducing sugar, glucose, and xylose yields of corn stover reached 478.5, 287.7, and 145.3mg/g raw biomass, respectively, indicating the viability of this novel pretreatment technology. PMID:22357289

  8. Life cycle assessment of switchgrass- and corn stover-derived ethanol-fueled automobiles.

    PubMed

    Spatari, Sabrina; Zhang, Yimin; MacLean, Heather L

    2005-12-15

    Utilizing domestically produced cellulose-derived ethanol for the light-duty vehicle fleet can potentially improve the environmental performance and sustainability of the transport and energy sectors of the economy. A life cycle assessment model was developed to examine environmental implications of the production and use of ethanol in automobiles in Ontario, Canada. The results were compared to those of low-sulfur reformulated gasoline (RFG) in a functionally equivalent automobile. Two time frames were evaluated, one near-term (2010), which examines converting a dedicated energy crop (switchgrass) and an agricultural residue (corn stover) to ethanol; and one midterm (2020), which assumes technological improvements in the switchgrass-derived ethanol life cycle. Near-term results show that, compared to a RFG automobile, life cycle greenhouse gas (GHG) emissions are 57% lower for an E85-fueled automobile derived from switchgrass and 65% lower for ethanol from corn stover, on a grams of CO2 equivalent per kilometer basis. Corn stover ethanol exhibits slightly lower life cycle GHG emissions, primarily due to sharing emissions with grain production. Through projected improvements in crop and ethanol yields, results for the mid-term scenario show that GHG emissions could be 25-35% lower than those in 2010 and that, even with anticipated improvements in RFG automobiles, E85 automobiles could still achieve up to 70% lower GHG emissions across the life cycle. PMID:16475363

  9. Speciation of Sulfur in Biochar Produced from Pyrolysis and Gasification of Oak and Corn Stover

    PubMed Central

    2015-01-01

    The effects of feedstock type and biomass conversion conditions on the speciation of sulfur in biochars are not well-known. In this study, the sulfur content and speciation in biochars generated from pyrolysis and gasification of oak and corn stover were determined. We found the primary determinant of the total sulfur content of biomass to be the feedstock from which the biochar is generated, with oak and corn stover biochars containing 160 and 600–800 ppm sulfur, respectively. In contrast, for sulfur speciation, we found the primary determinant to be the temperature combined with the thermochemical conversion method. The speciation of sulfur in biochars was determined using X-ray absorption near-edge structure (XANES), ASTM method D2492, and scanning electron microscopy–energy-dispersive spectroscopy (SEM–EDS). Biochars produced under pyrolysis conditions at 500–600 °C contain sulfate, organosulfur, and sulfide. In some cases, the sulfate contents are up to 77–100%. Biochars produced in gasification conditions at 850 °C contain 73–100% organosulfur. The increase of the organosulfur content as the temperature of biochar production increases suggests a similar sulfur transformation mechanism as that in coal, where inorganic sulfur reacts with hydrocarbon and/or H2 to form organosulfur when the coal is heated. EDS mapping of a biochar produced from corn stover pyrolysis shows individual sulfur-containing mineral particles in addition to the sulfur that is distributed throughout the organic matrix. PMID:25003702

  10. Advanced Biorefinery of Distriller's Grain and Corn Stover Blends

    SciTech Connect

    2006-04-01

    Fuel ethanol can be produced via the dry milling process, which converts corn grain to ethanol. The co-product, distiller’s grain (DG), is sold as a low-cost, high-protein feed source for livestock.

  11. Mathematical model parameters for describing the particle size spectra of knife-milled corn stover

    SciTech Connect

    Bitra, V.S.P; Womac, A.R.; Yang, Y.T.; Miu, P.I.; Igathanathane, C.

    2009-09-01

    Particle size distributions of Corn stover (Zea mays L.) created by a knife mill were determined using integral classifying screens with sizes from 12.7 to 50.8 mm, operating at speeds from 250 to 500 rpm, and mass input rates ranging from 1 to 9 kg min_1. Particle distributions were classified using American Society of Agricultural and Biological Engineers (ASABE) standardised sieves for forage analysis that incorporated a horizontal sieving motion. The sieves were made from machined-aluminium with their thickness proportional to the sieve opening dimensions. A wide range of analytical descriptors that could be used to mathematically represent the range of particle sizes in the distributions were examined. The correlation coefficients between geometric mean length and screen size, feed rate, and speed were 0.980, 0.612, and _0.027, respectively. Screen size and feed rate directly influenced particle size, whereas operating speed had a weak indirect relation with particle size. The Rosin Rammler equation fitted the chopped corn stover size distribution data with coefficient of determination (R2) > 0.978. This indicated that particle size distribution of corn stover was well-fit by the Rosin Rammler function. This can be attributed to the fact that Rosin Rammler expression was well suited to the skewed distribution of particle sizes. Skewed distributions occurred when significant quantities of particles, either finer or coarser, existed or were removed from region of the predominant size. The mass relative span was slightly greater than 1, which indicated that it was a borderline narrow to wide distribution of particle sizes. The uniformity coefficient was <4.0 for 19.0 50.8 mm screens, which indicated particles of relatively uniform size. Knife mill chopping of corn stover produced fine-skewed mesokurtic particles with 12.7 50.8 mm screens. Size-related parameters, namely, geometric mean length, Rosin Rammler size parameter, median length, effective length, and

  12. Crop productivity and soil resilience observed on short-term corn stover or cob harvest on several northern soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Highly productive soils are found throughout the US Corn Belt, in part due to their inherently high soil organic matter. Their productivity contributes to the high corn grain and stover yields; hence, this crop residue is predicted to be a significant bioenergy feedstock within this region. The obje...

  13. Corn Belt soil carbon and macronutrient budgets with projected sustainable stover harvest

    USGS Publications Warehouse

    Tan, Zhengxi; Liu, Shu-Guang

    2015-01-01

    Corn (Zea mays L.) stover has been identified as a prime feedstock for biofuel production in the U.S. Corn Belt because of its perceived abundance and availability, but long-term stover harvest effects on regional nutrient budgets have not been evaluated. We defined the minimum stover requirement (MSR) to maintain current soil organic carbon levels and then estimated current and future soil carbon (C), nitrogen (N), phosphorus (P), and potassium (K) budgets for various stover harvest scenarios. Analyses for 2006 through 2010 across the entire Corn Belt indicated that currently, 28 Tg or 1.6 Mg ha−1 of stover could be sustainably harvested from 17.95 million hectares (Mha) with N, P, and K removal of 113, 26, and 47 kg ha−1, respectively, and C removal for that period was estimated to be 4.55 Mg C ha−1. Assuming continued yield increases and a planted area of 26.74 Mha in 2050, 77.4 Tg stover (or 2.4 Mg ha−1) could be sustainably harvested with N, P, and K removal of 177, 37, and 72 kg ha−1, respectively, along with C removal of ∼6.57 Mg C ha−1. Although there would be significant variation across the region, harvesting only the excess over the MSR under current fertilization rates would result in a small depletion of soil N (−5 ± 27 kg ha−1) and K (−20 ± 31 kg ha−1) and a moderate surplus of P (36 ± 18 kg ha−1). Our 2050 projections based on continuing to keep the MSR, but having higher yields indicate that soil N and K deficits would become larger, thus emphasize the importance of balancing soil nutrient supply with crop residue removal.

  14. Changes in long-term no-till corn growth and yield under different rates of stover mulch

    SciTech Connect

    Blanco-Canqui, Dr. Humberto; Lal, Dr. Rattan; Post, Wilfred M; Owens, Lloyd

    2006-09-01

    Received for publication January 4, 2006. Removal of corn (Zea mays L.) stover for biofuel production may affect crop yields by altering soil properties. A partial stover removal may be feasible, but information on appropriate rates of removal is unavailable. We assessed the short-term impacts of stover management on long-term no-till (NT) continuous corn grown on a Rayne silt loam (fine loamy, mixed, active, mesic Typic Hapludults) at Coshocton, Hoytville clay loam (fine, illitic, mesic Mollic Epiaqualfs) at Hoytville, and Celina silt loam (fine, mixed, active, mesic Aquic Hapludalfs) at South Charleston in Ohio, and predicted corn yield from soil properties using principal component analysis (PCA). The study was conducted in 2005 on the ongoing experiments started in May 2004 under 0 (T0), 25 (T25), 50 (T50), 75 (T75), 100 (T100), and 200 (T200)% of stover corresponding to 0, 1.25, 2.50, 3.75, 5.00, and 10.00 Mg ha-1 of stover, respectively. Stover removal promoted early emergence and rapid seedling growth (P < 0.01). Early-emerging plants grew taller than late-emerging plants up to about 50 d, and then the heights reversed at Coshocton and were comparable at other two sites. Stover management affected corn yield only at the Coshocton site where average grain and stover yields in the T200, T100, T75, and T50 (10.8 and 10.3 Mg ha-1) were higher than those in the T0 and T25 treatments (8.5 and 6.5 Mg ha-1) (P < 0.01), showing that stover removal at rates as low as 50% (2.5 Mg ha-1) decreased crop yields. Soil properties explained 71% of the variability in grain yield and 33% of the variability in stover yield for the Coshocton site. Seventeen months after the start of the experiment, effects of stover management on corn yield and soil properties were site-specific.

  15. Soil microbial community response to corn stover harvesting under rain-fed, no-till conditions at multiple U.S. locations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Harvesting of corn stover for cellulosic ethanol production must be balanced with the requirement for returning plant residues to agricultural fields to maintain soil structure, fertility, crop protection, and other ecosystem services. High rates of corn stover removal can be associated with decrea...

  16. Degradation of corn stover by fungal cellulase cocktail for production of polyhydroxyalkanoates by moderate halophile Paracoccus sp. LL1.

    PubMed

    Sawant, Shailesh S; Salunke, Bipinchandra K; Kim, Beom Soo

    2015-10-01

    Bioprocessing of lignocellulose as a renewable resource for fuels, chemicals or value added products is a necessity to fulfil demands of petroleum products. This study aims to convert corn stover to polyhydroxyalkanoates (PHA). Corn stover was hydrolyzed to crude sugars by an on-site prepared cellulase cocktail from co-culture of Trichoderma reesei and Aspergillus niger. The potent PHA producer, Paracoccus sp. LL1, was isolated from Lonar Lake, India and could accumulate PHA up to 72.4% of its dry cell weight. PHA production reached 9.71 g/L from corn stover hydrolysate containing 40 g/L sugar mixture. The PHA synthase gene (phaC) sequence of the isolate showed 79% identity with the phaC gene of Paracoccus seriniphilus (E71) strain from the NCBI database. The nature/type of PHA was found to be poly(3-hydroxybutyrate) by Fourier transform infrared spectroscopy. PMID:26207871

  17. Solid state anaerobic co-digestion of tomato residues with dairy manure and corn stover for biogas production.

    PubMed

    Li, Yangyang; Li, Yu; Zhang, Difang; Li, Guoxue; Lu, Jiaxin; Li, Shuyan

    2016-10-01

    Solid-state anaerobic co-digestion of tomato residues with dairy manure and corn stover was conducted at 20% total solids under 35°C for 45days. Results showed digestion of mixed tomato residues with dairy manure and corn stover improved methane yields. The highest VS reduction (46.2%) and methane yield (415.4L/kg VSfeed) were achieved with the ternary mixtures of 33% corn stover, 54% dairy manure, and 13% tomato residues, lead to a 0.5-10.2-fold higher than that of individual feedstocks. Inhibition of volatile fatty acids (VFAs) to biogas production occurred when more than 40% tomato residues were added. The results indicated that ternary mixtures diluted the inhibitors that would otherwise cause inhibition in the digestion of tomato residues as a mono-feedstock. PMID:26922003

  18. Mechanical property of different corn stover morphological fractions and its correlations with high solids enzymatic hydrolysis by periodic peristalsis.

    PubMed

    Liu, Zhi-Hua; Chen, Hong-Zhang

    2016-08-01

    Selective structure fractionation combined with periodic peristalsis was exploited to improve the conversion performance of corn stover. The increase of glucan and lignin content and the decrease of xylan content in stem pith were highest after SE, whereas they were lowest in stem node. Glucan conversion increased in this order: steam nodecorn stover (WCS)corn stover morphological fractions. PMID:27140819

  19. Mold appearance and modeling on selected corn stover components during moisture sorption.

    PubMed

    Igathinathane, C; Womac, A R; Pordesimo, L O; Sokhansanj, S

    2008-09-01

    Occurrence of mold was visually monitored for 26days on samples of major anatomical components of corn stover maintained at several storage temperatures (T) and water activities (a(w)). Glass desiccators with saturated salt solutions placed in temperature controlled chambers provided simulated storage conditions with temperatures ranging from 10 degrees C to 40 degrees C and water activities ranging from 0.11 to 0.98. Mold affected leaf, stalk skin, and stalk pith equally at water activity greater than 0.9. As expected, a combination of increased water activity greater than 0.9 and temperatures greater than 30 degrees C was conducive to mold growth. Based on material moisture content during the initial mold growth, it was postulated that among the corn stover components the stalk pith was the least resistant to mold growth followed by stalk skin and leaf for the studied range of temperature and water activity. Mold growth models fitted well with the observation. A linear mold-free days predictions using a three-parameter regression model (T, a(w), and T x a(w)) was superior (R(2)=0.99) to other models considered. The exponential spoilage model using two parameter T and a(w) also gave comparable performance (R(2)=0.95). Among the independent factors, T x a(w) product was the most significant (p=0.0069) followed by T (p=0.0114), and a(w) (p=0.3140) in explaining the experimental data. The developed models can be applied to predict the safe storage period of corn stover components exposed to various temperature and moisture environmental conditions. PMID:18226891

  20. The Impact of Enzyme Characteristics on Corn Stover Fiber Degradation and Acid Production During Ensiled Storage

    NASA Astrophysics Data System (ADS)

    Ren, Haiyu; Richard, Tom L.; Moore, Kenneth J.

    Ensilage can be used to store lignocellulosic biomass before industrial bioprocessing. This study investigated the impacts of seven commerical enzyme mixtures derived from Aspergillus niger, Trichoderma reesei, and T. longibrachiatum. Treatments included three size grades of corn stover, two enzyme levels (1.67 and 5 IU/g dry matter based on hemicellulase), and various ratios of cellulase to hemicellulase (C ∶ H). The highest C ∶ H ratio tested, 2.38, derived from T. reesei, resulted in the most effective fermentation, with lactic acid as the dominant product. Enzymatic activity during storage may complement industrial pretreatment; creating synergies that could reduce total bioconversion costs.

  1. Techno-economic analysis of using corn stover to supply heat and power to a corn ethanol plant - Part 1: Cost of feedstock supply logistics

    SciTech Connect

    Sokhansanj, Shahabaddine; Mani, Sudhagar; Togore, Sam; Turhollow Jr, Anthony F

    2010-01-01

    Supply of corn stover to produce heat and power for a typical 170 dam3 dry mill ethanol plant is proposed. The corn ethanol plant requires 5.6 MW of electricity and 52.3 MW of process heat, which creates the annual stover demand of as much as 140 Gg. The corn stover supply system consists of collection, preprocessing, transportation and on-site fuel storage and preparation to produce heat and power for the ethanol plant. Economics of the entire supply system was conducted using the Integrated Biomass Supply Analysis and Logistics (IBSAL) simulation model. Corn stover was delivered in three formats (square bales, dry chops and pellets) to the combined heat and power plant. Delivered cost of biomass ready to be burned was calculated at 73 $ Mg-1 for bales, 86 $ Mg-1 for pellets and 84 $ Mg-1 for field chopped biomass. Among the three formats of stover supply systems, delivered cost of pelleted biomass was the highest due to high pelleting cost. Bulk transport of biomass in the form of chops and pellets can provide a promising future biomass supply logistic system in the US, if the costs of pelleting and transport are minimized.

  2. Enzymatic Digestibility of Corn Stover Fractions in Response to Fungal Pretreatment

    SciTech Connect

    Cui, Z. F.; Wan, C. X.; Shi, J.; Sykes, R. W.; Li, Y. B.

    2012-05-30

    Corn stover fractions (leaves, cobs, and stalks) were studied for enzymatic digestibility after pretreatment with a white rot fungus, Ceriporiopsis subvermispora. Among the three fractions, leaves had the least recalcitrance to fungal pretreatment and the lignin degradation reached 45% after 30 days of pretreatment. The lignin degradation of stalks and cobs was similar but was significantly lower than that of leaves (p < 0.05). For all fractions, xylan and glucan degradation followed a pattern similar to lignin degradation, with leaves having a significantly higher percentage of degradation (p < 0.05). Hydrolytic enzyme activity also revealed that the fungus was more active in the degradation of carbohydrates in leaves. As a result of fungal pretreatment, the highest sugar yield, however, was obtained with corn cobs.

  3. Impact of Collection Equipment on Ash Variability of Baled Corn Stover Biomass for Bioenergy

    SciTech Connect

    William Smith; Jeffery Einerson; Kevin Kenney; Ian J. Bonner

    2014-09-01

    Cost-effective conversion of agricultural residues for renewable energy hinges not only on the material’s quality but also the biorefinery’s ability to reliably measure quality specifications. The ash content of biomass is one such specification, influencing pretreatment and disposal costs for the conversion facility and the overall value of a delivered lot of biomass. The biomass harvest process represents a primary pathway for accumulation of soil-derived ash within baled material. In this work, the influence of five collection techniques on the total ash content and variability of ash content within baled corn stover in southwest Kansas is discussed. The equipment tested included a mower for cutting the corn stover stubble, a basket rake, wheel rake, or shred flail to gather the stover, and a mixed or uniform in-feed baler for final collection. The results showed mean ash content to range from 11.5 to 28.2 % depending on operational choice. Resulting impacts on feedstock costs for a biochemical conversion process range from $5.38 to $22.30 Mg-1 based on the loss of convertible dry matter and ash disposal costs. Collection techniques that minimized soil contact (shred flail or nonmowed stubble) were shown to prevent excessive ash contamination, whereas more aggressive techniques (mowing and use of a wheel rake) caused greater soil disturbance and entrainment within the final baled material. Material sampling and testing were shown to become more difficult as within-bale ash variability increased, creating uncertainty around feedstock quality and the associated costs of ash mitigation.

  4. Effect of sulfuric and phosphoric acid pretreatments on enzymatic hydrolysis of corn stover.

    PubMed

    Um, Byung-Hwan; Karim, M; Henk, Linda

    2003-01-01

    The pretreatment of corn stover with H2SO4 and H3PO4 was investigated. Pretreatments were carried out from 30 to 120 min in a batch reactor at 121 degrees C, with acid concentrations ranging from 0 to 2% (w/v) at a solid concentration of 5% (w/v). Pretreated corn stover was washed with distilled water until the filtrate was adjusted to pH 7.0, followed by surfactant swelling of the cellulosic fraction in a 0-10% (w/v) solution of Tween-80 at room temperature for 12 h. The dilute acid treatment proved to be a very effective method in terms of hemicellulose recovery and cellulose digestibility. Hemicellulose recovery was 62-90%, and enzymatic digestibility of the cellulose that remained in the solid was >80% with 2% (w/v) acid. In all cases studied, the performance of H2SO4 pretreatment (hemicellulose recovery and cellulose digestibility) was significantly better than obtained with H3PO4. Enzymatic hydrolysis was more effective using surfactant than without it, producing 10-20% more sugar. Furthermore, digestibility was investigated as a function of hemicellulose removal. It was found that digestibility was more directly related to hemicellulose removal than to delignification. PMID:12721479

  5. Comparison of different ionic liquids pretreatment for corn stover enzymatic saccharification.

    PubMed

    Mood, Sohrab Haghighi; Golfeshan, Amir Hossein; Tabatabaei, Meisam; Abbasalizadeh, Saeed; Ardjmand, Mehdi; Jouzani, Gholamreza Salehi

    2014-01-01

    Recently, application of ionic liquids (ILs) has received much attention due to their special solvency properties as a promising method of pretreatment for lignocellulosic biomass. Easy recovery of ionic liquids, chemical stability, temperature stability, nonflammability, low vapor pressure, and wide liquidus range are among those unique properties. These solvents are also known as green solvents due to their low vapor pressure. The present study was set to compare the effect of five different ILs, namely, 1-ethyl-3-methylimidazolium acetate ([EMIM][Ac]), 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]), 1-ethyl-3-methyl imidazolium diethyl phosphate ([EMIM][DEP]), 1-allyl-3-methylimidazolium chloride ([AMIM][Cl]), and 1-ethyl-3-methylimidazolium-hydrogen sulfate ([EMIM][HSO₄]), on corn stover in a bioethanol production process. The performance of ILs was evaluated based on the change observed in chemical structure, crystallinity index, cellulose digestibility, and glucose release. Overall, [EMIM][Ac]-pretreated corn stover led to significantly higher saccharification, with cellulose digestibility reaching 69% after 72 hr, whereas digestibility of untreated barley straw was measured at only 21%. PMID:24397717

  6. Enhancing cellulose accessibility of corn stover by deep eutectic solvent pretreatment for butanol fermentation.

    PubMed

    Xu, Guo-Chao; Ding, Ji-Cai; Han, Rui-Zhi; Dong, Jin-Jun; Ni, Ye

    2016-03-01

    In this study, an effective corn stover (CS) pretreatment method was developed for biobutanol fermentation. Deep eutectic solvents (DESs), consisted of quaternary ammonium salts and hydrogen donors, display similar properties to room temperature ionic liquid. Seven DESs with different hydrogen donors were facilely synthesized. Choline chloride:formic acid (ChCl:formic acid), an acidic DES, displayed excellent performance in the pretreatment of corn stover by removal of hemicellulose and lignin as confirmed by SEM, FTIR and XRD analysis. After optimization, glucose released from pretreated CS reached 17.0 g L(-1) and yield of 99%. The CS hydrolysate was successfully utilized in butanol fermentation by Clostridium saccharobutylicum DSM 13864, achieving butanol titer of 5.63 g L(-1) with a yield of 0.17 g g(-1) total sugar and productivity of 0.12 g L(-1)h(-1). This study demonstrates DES could be used as a promising and biocompatible pretreatment method for the conversion of lignocellulosic biomass into biofuel. PMID:26597485

  7. Impact of Cell Wall Acetylation on Corn Stover Hydrolysis by Cellulolytic and Xylanolytic Enzymes

    SciTech Connect

    Selig, M. J.; Adney, W. S.; Himmel, M. E.; Decker, S. R.

    2009-01-01

    Analysis of variously pretreated corn stover samples showed neutral to mildly acidic pretreatments were more effective at removing xylan from corn stover and more likely to maintain the acetyl to xylopyranosyl ratios present in untreated material than were alkaline treatments. Retention of acetyl groups in the residual solids resulted in greater resistance to hydrolysis by endoxylanase alone, although the synergistic combination of endoxylanase and acetyl xylan esterase enzymes permitted higher xylan conversions to be observed. Acetyl xylan esterase alone did little to improve hydrolysis by cellulolytic enzymes, although a direct relationship was observed between the enzymatic removal of acetyl groups and improvements in the enzymatic conversion of xylan present in substrates. In all cases, effective xylan conversions were found to significantly improve glucan conversions achievable by cellulolytic enzymes. Additionally, acetyl and xylan removal not only enhanced the respective initial rates of xylan and glucan conversion, but also the overall extents of conversion. This work emphasizes the necessity for xylanolytic enzymes during saccharification processes and specifically for the optimization of acetyl esterase and xylanase synergies when biomass processes include milder pretreatments, such as hot water or sulfite steam explosion.

  8. Corn stover harvest increases herbicide movement to subsurface drains: RZWQM simulations

    USGS Publications Warehouse

    Shipitalo, Martin J.; Malone, Robert W.; Ma, Liwang; Nolan, Bernard T.; Kanwar, Rameshwar S.; Shaner, Dale L.; Pederson, Carl H.

    2016-01-01

    BACKGROUND Crop residue removal for bioenergy production can alter soil hydrologic properties and the movement of agrochemicals to subsurface drains. The Root Zone Water Quality Model (RZWQM), previously calibrated using measured flow and atrazine concentrations in drainage from a 0.4 ha chisel-tilled plot, was used to investigate effects of 50 and 100% corn (Zea mays L.) stover harvest and the accompanying reductions in soil crust hydraulic conductivity and total macroporosity on transport of atrazine, metolachlor, and metolachlor oxanilic acid (OXA). RESULTS The model accurately simulated field-measured metolachlor transport in drainage. A 3-yr simulation indicated that 50% residue removal decreased subsurface drainage by 31% and increased atrazine and metolachlor transport in drainage 4 to 5-fold when surface crust conductivity and macroporosity were reduced by 25%. Based on its measured sorption coefficient, ~ 2-fold reductions in OXA losses were simulated with residue removal. CONCLUSION RZWQM indicated that if corn stover harvest reduces crust conductivity and soil macroporosity, losses of atrazine and metolachlor in subsurface drainage will increase due to reduced sorption related to more water moving through fewer macropores. Losses of the metolachlor degradation product OXA will decrease due to the more rapid movement of the parent compound into the soil.

  9. EFFECT OF ANATOMICAL FRACTIONATION ON THE ENZYMATIC HYDROLYSIS OF ACID AND ALKALINE PRETREATED CORN STOVER

    SciTech Connect

    K. B. Duguid; M. D. Montross; C. W. Radtke; C. L. Crofcheck; L. M. Wendt; S. A. Shearer

    2009-11-01

    Due to concerns with biomass collection systems and soil sustainability there are opportunities to investigate the optimal plant fractions to collect for conversion. An ideal feedstock would require low severity pretreatment to release a maximum amount of sugar during enzymatic hydrolysis. Corn stover fractions were separated by hand and analyzed for glucan, xylan, acid soluble lignin, acid insoluble lignin, and ash composition. The stover fractions were also pretreated with either 0, 0.4, or 0.8% NaOH for 2 hours at room temperature, washed, autoclaved and saccharified. In addition, acid pretreated samples underwent simultaneous saccharification and fermentation (SSF) to ethanol. In general, the two pretreatments produced similar trends with cobs, husks, and leaves responding best to the pretreatments, the tops of stalks responding slightly less, and the bottom of the stalks responding the least. For example, corn husks pretreated with 0.8% NaOH released over 90% (standard error of 3.8%) of the available glucan, while only 45% (standard error of 1.1%) of the glucan was produced from identically treated stalk bottoms. Estimates of the theoretical ethanol yield using acid pretreatment followed by SSF were 65% (standard error of 15.9%) for husks and 29% (standard error of 1.8%) for stalk bottoms. This suggests that integration of biomass collection systems to remove sustainable feedstocks could be integrated with the processes within a biorefinery to minimize overall ethanol production costs.

  10. Three-stage hydrolysis to enhance enzymatic saccharification of steam-exploded corn stover.

    PubMed

    Yang, Jing; Zhang, Xiaoping; Yong, Qiang; Yu, Shiyuan

    2010-07-01

    The objective of the present research was to explore new approach to reduce the hydrolysis time and to enhance the productivity of enzymatic saccharification. One-stage hydrolysis of steam-exploded corn stover required 72 h to reach a yield of 62.8%, while multi-stage hydrolysis could reduce the time to 24 h. A concept of three-stage hydrolysis was therefore proposed in which cellulosic substrate was hydrolyzed for 6, 6, and 12 h, respectively. High hydrolysis yields, 70.2% with enzyme recycling and 76.1% with the supplement of fresh enzyme to eliminate enzyme recovery procedure, were obtained in 24 h. Analysis indicated that short-time hydrolysis and the removal of end products at each stage improved cellulase activities and benefited the adsorption of cellulase enzyme to the solid substrate. When steam-exploded corn stover was used as the substrate for cellulase synthesis, a hydrolysis yield of 88.6% was achieved in 24 h. PMID:19857959

  11. Effect of hemicellulose and lignin removal on enzymatic hydrolysis of steam pretreated corn stover.

    PubMed

    Ohgren, Karin; Bura, Renata; Saddler, Jack; Zacchi, Guido

    2007-09-01

    Ethanol can be produced from lignocellulosic biomass using steam pretreatment followed by enzymatic hydrolysis and fermentation. The sugar yields, from both hemicellulose and cellulose are critical parameters for an economically-feasible ethanol production process. This study shows that a near-theoretical glucose yield (96-104%) from acid-catalysed steam pretreated corn stover can be obtained if xylanases are used to supplement cellulases during hydrolysis. Xylanases hydrolyse residual hemicellulose, thereby improving the access of enzymes to cellulose. Under these conditions, xylose yields reached 70-74%. When pre-treatment severity was reduced by using autocatalysis instead of acid-catalysed steam pretreatment, xylose yields were increased to 80-86%. Partial delignification of pretreated material was also evaluated as a way to increase the overall sugar yield. The overall glucose yield increased slightly due to delignification but the overall xylose yield decreased due to hemicellulose loss in the delignification step. The data also demonstrate that steam pretreatment is a robust process: corn stover from Europe and North America showed only minor differences in behaviour. PMID:17113771

  12. Influence of physico-chemical changes on enzymatic digestibility of ionic liquid and AFEX pretreated corn stover.

    PubMed

    Li, Chenlin; Cheng, Gang; Balan, Venkatesh; Kent, Michael S; Ong, Markus; Chundawat, Shishir P S; Sousa, Leonardo daCosta; Melnichenko, Yuri B; Dale, Bruce E; Simmons, Blake A; Singh, Seema

    2011-07-01

    Ionic liquid (IL) and ammonia fiber expansion (AFEX) pretreatments were studied to develop the first direct side-by-side comparative assessment on their respective impacts on biomass structure, composition, process mass balance, and enzymatic saccharification efficiency. AFEX pretreatment completely preserves plant carbohydrates, whereas IL pretreatment extracts 76% of hemicellulose. In contrast to AFEX, the native crystal structure of the recovered corn stover from IL pretreatment was significantly disrupted. For both techniques, more than 70% of the theoretical sugar yield was attained after 48 h of hydrolysis using commercial enzyme cocktails. IL pretreatment requires less enzyme loading and a shorter hydrolysis time to reach 90% yields. Hemicellulase addition led to significant improvements in the yields of glucose and xylose for AFEX pretreated corn stover, but not for IL pretreated stover. These results provide new insights into the mechanisms of IL and AFEX pretreatment, as well as the advantages and disadvantages of each. PMID:21531133

  13. Influence of Physico-Chemical Changes on Enzymatic Digestibility of Ionic Liquid and AFEX pretreated Corn Stover

    SciTech Connect

    Li, Chenlin; Cheng, Gang; Kent, Michael S; Ong, Markus; Balan, Venkatesh; Dale, Bruce E.; Melnichenko, Yuri B; Simmons, Blake

    2011-01-01

    Ionic liquid (IL) and ammonia fiber expansion (AFEX) pretreatments were studied to develop the first direct side-by-side comparative assessment on their respective impacts on biomass structure, composition, process mass balance, and enzymatic saccharification efficiency. AFEX pretreatment completely preserves plant carbohydrates, whereas IL pretreatment extracts 76% of hemicellulose. In contrast to AFEX, the native crystal structure of the recovered corn stover from IL pretreatment was significantly disrupted. For both techniques, more than 70% of the theoretical sugar yield was attained after 48 h of hydrolysis using commercial enzyme cocktails. IL pretreatment requires less enzyme loading and a shorter hydrolysis time to reach 90% yields. Hemicellulase addition led to significant improvements in the yields of glucose and xylose for AFEX pretreated corn stover, but not for IL pretreated stover. These results provide new insights into the mechanisms of IL and AFEX pretreatment, as well as the advantages and disadvantages of each.

  14. Chemical properties and antioxidant activity of exopolysaccharides fractions from mycelial culture of Inonotus obliquus in a ground corn stover medium.

    PubMed

    Xiang, Yuling; Xu, Xiangqun; Li, Juan

    2012-10-15

    The medicinal mushroom Inonotus obliquus has been a folk remedy for a long time in East-European and Asian countries. We first reported the enhancement in production and antioxidant activity of exopolysaccharides by I. obliquus culture under lignocellulose decomposition. In this study, the two different sources of exopolysaccharides from the control medium and the lignocellulose (corn stover) containing medium by I. obliquus in submerged fermentation were fractionated and purified by chromatography. The exopolysaccharides from the corn stover-containing medium presented significantly stronger hydroxyl and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity than the control. Three fractions from the control medium and the corn stover-containing medium were isolated respectively. The fraction of DEPL3 from the corn stover-containing medium with the highest protein content (38.3%), mannose content (49.6%), and the lowest molecular weight (29 kDa) had the highest antioxidant activity with the lowest IC50 values. In conclusion, lignocellulose decomposition changed the chemical characterisation and significantly enhanced the antioxidant activity of exopolysaccharide fractions. PMID:23442636

  15. Response surface optimization of corn stover pretreatment using dilute phosphoric acid for enzymatic hydrolysis and ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dilute H3PO4 (0.0 - 2.0%, v/v) was used to pretreat corn stover (10%, w/w) for conversion to ethanol. Pretreatment conditions were optimized for temperature, acid loading, and time using a central composite design. Optimal pretreatment conditions were chosen to promote sugar yields following enzym...

  16. ON-FARM PRETREATMENT TECHNOLOGIES FOR IMPROVING ENZYMATIC DIGESTIBILITY OF CELLULOSE AND HEMICELLULOSE PRESENT IN PERENNIAL GRASS AND CORN STOVER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recently, wet storage methods have been proposed for feedstock preservation and on-farm storage of perennial grass and corn stover biomass. The advantages over a dry storage system include lower risk of fire, reduced harvest costs, and improved feedstock susceptibility to enzymatic hydrolysis. We ...

  17. Response surface optimization of corn stover pretreatment using dilute phosphoric acid for enzymatic hydrolysis and ethanol production.

    PubMed

    Avci, Ayse; Saha, Badal C; Dien, Bruce S; Kennedy, Gregory J; Cotta, Michael A

    2013-02-01

    Dilute H(3)PO(4) (0.0-2.0%, v/v) was used to pretreat corn stover (10%, w/w) for conversion to ethanol. Pretreatment conditions were optimized for temperature, acid loading, and time using central composite design. Optimal pretreatment conditions were chosen to promote sugar yields following enzymatic digestion while minimizing formation of furans, which are potent inhibitors of fermentation. The maximum glucose yield (85%) was obtained after enzymatic hydrolysis of corn stover pretreated with 0.5% (v/v) acid at 180°C for 15min while highest yield for xylose (91.4%) was observed from corn stover pretreated with 1% (v/v) acid at 160°C for 10min. About 26.4±0.1g ethanol was produced per L by recombinant Escherichia coli strain FBR5 from 55.1±1.0g sugars generated from enzymatically hydrolyzed corn stover (10%, w/w) pretreated under a balanced optimized condition (161.81°C, 0.78% acid, 9.78min) where only 0.4±0.0g furfural and 0.1±0.0 hydroxylmethyl furfural were produced. PMID:23334017

  18. Methane enhancement through oxidative cleavage and alkali solubilization pre-treatments for corn stover with anaerobic activated sludge.

    PubMed

    Hassan, Muhammad; Ding, Weimin; Bi, Jinhua; Mehryar, Esmaeil; Talha, Zahir Ahmed Ali; Huang, Hongying

    2016-01-01

    In the present study, thermo-chemical pre-treatment was adopted to evaluate methane production potential from corn stover by co-digesting it with anaerobic activated sludge. Three chemicals H2O2, Ca(OH)2 and NaOH were selected with two levels of concentration. All thermo-chemical pre-treatments were found significant (P<0.05) to enhance lignocellulosic digestibility and methane production. The results indicated that the methane yield by H2O2-1, H2O2-2, and NaOH-2 treated corn stover were 293.52, 310.50 and 279.42ml/g.VS which were 57.18%, 66.27% and 49.63% higher than the untreated corn stover respectively. In the previous studies pre-treatment time was reported in days but our method had reduced it to about one hour. H2O2-2 and NaOH-2 treatments remained prominent to increase lignocellulosic degradation vigorously up to 45% and 42% respectively. Process biochemistry during the anaerobic digestion process was taken into consideration to optimize the most feasible thermo-chemical pre-treatment for corn stover. PMID:26512865

  19. Production of Butanol (a Biofuel) from Agricultural Residues: Part II - Use of Corn Stover and Switchgrass Hydrolysates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Acetone butanol ethanol (ABE or AB, or solvent) was produced from hydrolyzed corn stover and switchgrass using Clostridium beijerinckii P260. A control experiment using glucose resulted in the production of 21.06 gL**-1 total ABE. In this experiment, an AB yield and productivity of 0.41 and 0.31 g...

  20. Bioconversion of barley straw and corn stover to butanol (a biofuel) in integrated fermentation and simultaneous product recovery bioreactors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In these studies concentrated sugar solutions of barley straw and corn stover hydrolysates were fermented with simultaneous product recovery and compared with the performance of a control glucose batch fermentation process. The control glucose batch fermentation resulted in the production of 23.25 g...

  1. The impact of corn stover removal on N2O emission and soil respiration: An investigation with automated chambers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover removal, whether for silage, bedding, or bioenergy production, could have a variety of environmental consequences through its effect on soil processes, particularly N2O production and soil respiration. Because these effects may be episodic in nature, weekly snapshots with static chambers...

  2. MBI Biorefinery: Corn to Biomass, Ethanol to Biochemicals and Biomaterials

    SciTech Connect

    2006-02-17

    The project is a continuation of DOE-funded work (FY02 and FY03) that has focused on the development of the ammonia fiber explosion (AFEX) pretreatment technology, fermentation production of succinic acid and new processes and products to enhance dry mill profitability. The primary objective for work beginning in April 2004 and ending in November 2005 is focus on the key issues related to the: (1) design, costing and construction plan for a pilot AFEX pretreatment system, formation of a stakeholder development team to assist in the planning and design of a biorefinery pilot plant, continued evaluation of corn fractionation technologies, corn oil extraction, AFEX treatment of corn fiber/DDGs; (2) development of a process to fractionate AFEX-treated corn fiber and corn stover--cellulose and hemicellulose fractionation and sugar recovery; and (3) development of a scalable batch succinic acid production process at 500 L at or below $.42/lb, a laboratory scale fed-batch process for succinic acid production at or below $.40/lb, a recovery process for succinic acid that reduces the cost of succinic acid by $.02/lb and the development of an acid tolerant succinic acid production strain at lab scale (last objective not to be completed during this project time period).

  3. Prospects for Simultaneous Improvement of Corn Grain Yield and Stover Quality for Cellulosic Ethanol: Quantitative Genetic Parameters, Genetic Value Predictions, and QTL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) has been bred for increased grain yield but not for stover quality for cellulosic ethanol production. Our objectives were to: (1) identify potential barriers, at the quantitative trait and molecular marker level, for simultaneous improvement of grain yield and stover quality; (2) ...

  4. Drought effects on composition and yield for corn stover, mixed grasses, and Miscanthus as bioenergy feedstocks

    DOE PAGESBeta

    Emerson, Rachel; Hoover, Amber; Ray, Allison; Lacey, Jeffrey; Cortez, Marnie; Payne, Courtney; Karlen, Douglas; Birrell, Stuart; Laird, David; Kallenbach, Robert; et al

    2014-07-04

    Drought conditions in 2012 were some of the most severe in recent history. The purpose of this study is to examine the impact of drought on quality, quantity, and theoretical ethanol yield (TEY) of three bioenergy feedstocks, corn stover, mixed grasses from Conservation Reserve Program lands, and Miscanthus × giganteus. To assess drought effects on these feedstocks, samples from 2010 (minimal to no drought) and 2012 (severe drought) were compared from multiple locations in the US. In all feedstocks, drought significantly increased extractives and reduced structural sugars and lignin; subsequently, TEYs were reduced 10–15%. Biomass yields were significantly reduced formore » M. × giganteus and mixed grasses. When reduction in quality and quantity were combined, TEYs decreased 26–59%. Drought negatively affected biomass quality and quantity that resulted in significant TEY reductions. As a result, such fluctuations in biomass quality and yield may have significant consequences for developing lignocellulosic biorefineries.« less

  5. Catalytic production of biofuels (butene oligomers) and biochemicals (tetrahydrofurfuryl alcohol) from corn stover.

    PubMed

    Byun, Jaewon; Han, Jeehoon

    2016-07-01

    A strategy is presented that produces liquid hydrocarbon fuels (butene oligomers (BO)) from cellulose (C6) fraction and commodity chemicals (tetrahydrofurfuryl alcohol (THFA)) from hemicellulose (C5) of corn stover based on catalytic conversion technologies using 2-sec-butylphenol (SBP) solvents. This strategy integrates the conversion subsystems based on experimental studies and separation subsystems for recovery of biomass derivatives and SBP solvents. Moreover, a heat exchanger network is designed to reduce total heating requirements to the lowest level, which is satisfied from combustion of biomass residues (lignin and humins). Based on the strategy, this work offers two possible process designs (design A: generating electricity internally vs. design B: purchasing electricity externally), and performs an economic feasibility study for both the designs based on a comparison of the minimum selling price (MSP) of THFA. This strategy with the design B leads to a better MSP of $1.93 per kg THFA. PMID:27030955

  6. High Xylose Yields from Dilute Acid Pretreatment of Corn Stover Under Process-Relevant Conditions

    SciTech Connect

    Weiss, N. D.; Nagle, N. J.; Tucker, M. P.; Elander, R. T.

    2009-01-01

    Pretreatment experiments were carried out to demonstrate high xylose yields at high solids loadings in two different batch pretreatment reactors under process-relevant conditions. Corn stover was pretreated with dilute sulfuric acid using a 4-l Steam Digester and a 4-l stirred ZipperClave{reg_sign} reactor. Solids were loaded at 45% dry matter (wt/wt) after sulfuric acid catalyst impregnation using nominal particle sizes of either 6 or 18 mm. Pretreatment was carried out at temperatures between 180 and 200 C at residence times of either 90 or 105 s. Results demonstrate an ability to achieve high xylose yields (>80%) over a range of pretreatment conditions, with performance showing little dependence on particle size or pretreatment reactor type. The high xylose yields are attributed to effective catalyst impregnation and rapid rates of heat transfer during pretreatment.

  7. Pretreatment combining ultrasound and sodium percarbonate under mild conditions for efficient degradation of corn stover.

    PubMed

    Nakashima, Kazunori; Ebi, Yuuki; Kubo, Masaki; Shibasaki-Kitakawa, Naomi; Yonemoto, Toshikuni

    2016-03-01

    Ultrasound (US) can be used to disrupt microcrystalline cellulose to give nanofibers via ultrasonic cavitation. Sodium percarbonate (SP), consisting of sodium carbonate and hydrogen peroxide, generates highly reactive radicals, which cause oxidative delignification. Here, we describe a novel pretreatment technique using a combination of US and SP (US-SP) for the efficient saccharification of cellulose and hemicellulose in lignocellulosic corn stover. Although US-SP pretreatment was conducted under mild condition (i.e., at room temperature and atmospheric pressure), the pretreatment greatly increased lignin removal and cellulose digestibility. We also determined the optimum US-SP treatment conditions, such as ultrasonic power output, pretreatment time, pretreatment temperature, and SP concentration for an efficient cellulose saccharification. Moreover, xylose could be effectively recovered from US-SP pretreated biomass without the formation of microbial inhibitor furfural. PMID:26547502

  8. Ruminal Methanogen Community in Dairy Cows Fed Agricultural Residues of Corn Stover, Rapeseed, and Cottonseed Meals.

    PubMed

    Wang, Pengpeng; Zhao, Shengguo; Wang, Xingwen; Zhang, Yangdong; Zheng, Nan; Wang, Jiaqi

    2016-07-13

    The purpose was to reveal changes in the methanogen community in the rumen of dairy cows fed agricultural residues of corn stover, rapeseed, and cottonseed meals, compared with alfalfa hay or soybean meal. Analysis was based on cloning and sequencing the methyl coenzyme M reductase α-subunit gene of ruminal methanogens. Results revealed that predicted methane production was increased while population of ruminal methanogens was not significantly affected when cows were fed diets containing various amounts of agricultural residues. Richness and diversity of methanogen community were markedly increased by addition of agricultural residues. The dominant ruminal methanogens shared by all experimental groups belonged to rumen cluster C, accounting for 71% of total, followed by the order Methanobacteriales (29%). Alterations of ruminal methanogen community and prevalence of particular species occurred in response to fed agricultural residue rations, suggesting the possibility of regulating target methanogens to control methane production by dairy cows fed agricultural residues. PMID:27322573

  9. A low-cost solid–liquid separation process for enzymatically hydrolyzed corn stover slurries

    SciTech Connect

    Sievers, David A.; Lischeske, James J.; Biddy, Mary J.; Stickel, Jonathan J.

    2015-07-01

    Solid-liquid separation of intermediate process slurries is required in some process configurations for the conversion of lignocellulosic biomass to transportation fuels. Thermochemically pretreated and enzymatically hydrolyzed corn stover slurries have proven difficult to filter due to formation of very low permeability cakes that are rich in lignin. Treatment of two different slurries with polyelectrolyte flocculant was demonstrated to increase mean particle size and filterability. Filtration flux was greatly improved, and thus scaled filter unit capacity was increased approximately 40-fold compared with unflocculated slurry. Although additional costs were accrued using polyelectrolyte, techno-economic analysis revealed that the increase in filter capacity significantly reduced overall production costs. Fuel production cost at 95% sugar recovery was reduced by $1.35 US per gallon gasoline equivalent for dilute-acid pretreated and enzymatically hydrolyzed slurries and $3.40 for slurries produced using an additional alkaline de-acetylation preprocessing step that is even more difficult to natively filter.

  10. Correlating Detergent Fiber Analysis and Dietary Fiber Analysis Data for Corn Stover

    SciTech Connect

    Wolfrum, E. J.; Lorenz, A. J.; deLeon, N.

    2009-01-01

    There exist large amounts of detergent fiber analysis data [neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL)] for many different potential cellulosic ethanol feedstocks, since these techniques are widely used for the analysis of forages. Researchers working in the area of cellulosic ethanol are interested in the structural carbohydrates in a feedstock (principally glucan and xylan), which are typically determined by acid hydrolysis of the structural fraction after multiple extractions of the biomass. These so-called dietary fiber analysis methods are significantly more involved than detergent fiber analysis methods. The purpose of this study was to determine whether it is feasible to correlate detergent fiber analysis values to glucan and xylan content determined by dietary fiber analysis methods for corn stover. In the detergent fiber analysis literature cellulose is often estimated as the difference between ADF and ADL, while hemicellulose is often estimated as the difference between NDF and ADF. Examination of a corn stover dataset containing both detergent fiber analysis data and dietary fiber analysis data predicted using near infrared spectroscopy shows that correlations between structural glucan measured using dietary fiber techniques and cellulose estimated using detergent techniques, and between structural xylan measured using dietary fiber techniques and hemicellulose estimated using detergent techniques are high, but are driven largely by the underlying correlation between total extractives measured by fiber analysis and NDF/ADF. That is, detergent analysis data is correlated to dietary fiber analysis data for structural carbohydrates, but only indirectly; the main correlation is between detergent analysis data and solvent extraction data produced during the dietary fiber analysis procedure.

  11. Comparison of enzymatic reactivity of corn stover solids prepared by dilute acid, AFEX™, and ionic liquid pretreatments

    PubMed Central

    2014-01-01

    Background Pretreatment is essential to realize high product yields from biological conversion of naturally recalcitrant cellulosic biomass, with thermochemical pretreatments often favored for cost and performance. In this study, enzymatic digestion of solids from dilute sulfuric acid (DA), ammonia fiber expansion (AFEX™), and ionic liquid (IL) thermochemical pretreatments of corn stover were followed over time for the same range of total enzyme protein loadings to provide comparative data on glucose and xylose yields of monomers and oligomers from the pretreated solids. The composition of pretreated solids and enzyme adsorption on each substrate were also measured to determine. The extent glucose release could be related to these features. Results Corn stover solids from pretreatment by DA, AFEX, and IL were enzymatically digested over a range of low to moderate loadings of commercial cellulase, xylanase, and pectinase enzyme mixtures, the proportions of which had been previously optimized for each pretreatment. Avicel® cellulose, regenerated amorphous cellulose (RAC), and beechwood xylan were also subjected to enzymatic hydrolysis as controls. Yields of glucose and xylose and their oligomers were followed for times up to 120 hours, and enzyme adsorption was measured. IL pretreated corn stover displayed the highest initial glucose yields at all enzyme loadings and the highest final yield for a low enzyme loading of 3 mg protein/g glucan in the raw material. However, increasing the enzyme loading to 12 mg/g glucan or more resulted in DA pretreated corn stover attaining the highest longer-term glucose yields. Hydrolyzate from AFEX pretreated corn stover had the highest proportion of xylooligomers, while IL produced the most glucooligomers. However, the amounts of both oligomers dropped with increasing enzyme loadings and hydrolysis times. IL pretreated corn stover had the highest enzyme adsorption capacity. Conclusions Initial hydrolysis yields were highest

  12. Detecting Cellulase Penetration Into Corn Stover Cell Walls by Immuno-Electron Microscopy

    SciTech Connect

    Donohoe, B. S.; Selig, M. J.; Viamajala, S.; Vinzant, T. B.; Adney, W. S.; Himmel, M. E.

    2009-06-15

    In general, pretreatments are designed to enhance the accessibility of cellulose to enzymes, allowing for more efficient conversion. In this study, we have detected the penetration of major cellulases present in a commercial enzyme preparation (Spezyme CP) into corn stem cell walls following mild-, moderate- and high-severity dilute sulfuric acid pretreatments. The Trichoderma reesei enzymes, Cel7A (CBH I) and Cel7B (EG I), as well as the cell wall matrix components xylan and lignin were visualized within digested corn stover cell walls by immuno transmission electron microscopy (TEM) using enzyme- and polymer-specific antibodies. Low severity dilute-acid pretreatment (20 min at 100 C) enabled <1% of the thickness of secondary cell walls to be penetrated by enzyme, moderate severity pretreatment at (20 min at 120 C) allowed the enzymes to penetrate {approx}20% of the cell wall, and the high severity (20 min pretreatment at 150 C) allowed 100% penetration of even the thickest cell walls. These data allow direct visualization of the dramatic effect dilute-acid pretreatment has on altering the condensed ultrastructure of biomass cell walls. Loosening of plant cell wall structure due to pretreatment and the subsequently improved access by cellulases has been hypothesized by the biomass conversion community for over two decades, and for the first time, this study provides direct visual evidence to verify this hypothesis. Further, the high-resolution enzyme penetration studies presented here provide insight into the mechanisms of cell wall deconstruction by cellulolytic enzymes.

  13. Combined process for ethanol fermentation at high-solids loading and biogas digestion from unwashed steam-exploded corn stover.

    PubMed

    Wang, Zhen; Lv, Zhe; Du, Jiliang; Mo, Chunling; Yang, Xiushan; Tian, Shen

    2014-08-01

    A combined process was designed for the co-production of ethanol and methane from unwashed steam-exploded corn stover. A terminal ethanol titer of 69.8 g/kg mass weight (72.5%) was achieved when the fed-batch mode was performed at a final solids loading of 35.5% (w/w) dry matter (DM) content. The whole stillage from high-solids ethanol fermentation was directly transferred in a 3-L anaerobic digester. During 52-day single-stage digester operation, the methane productivity was 320 mL CH₄/g volatile solids (VS) with a maximum VS reduction efficiency of 55.3%. The calculated overall product yield was 197 g ethanol + 96 g methane/kg corn stover. This indicated that the combined process was able to improve overall content utilization and extract a greater yield of lignocellulosic biomass compared to ethanol fermentation alone. PMID:24926600

  14. A novel diffusion-biphasic hydrolysis coupled kinetic model for dilute sulfuric acid pretreatment of corn stover.

    PubMed

    Chen, Longjian; Zhang, Haiyan; Li, Junbao; Lu, Minsheng; Guo, Xiaomiao; Han, Lujia

    2015-02-01

    Kinetic experiments on the dilute sulfuric acid pretreatment of corn stover were performed. A high xylan removal and a low inhibitor concentration were achieved by acid pretreatment. A novel diffusion-hydrolysis coupled kinetic model was proposed. The contribution to the xylose yield was analyzed by the kinetic model. Compared with the inhibitor furfural negatively affecting xylose yield, the fast and slow-hydrolyzing xylan significantly contributed to the xylose yield, however, their dominant roles were dependent on reaction temperature and time. The impact of particle size and acid concentration on the xylose yield were also investigated. The diffusion process may significantly influence the hydrolysis of large particles. Increasing the acid concentration from 0.15 M to 0.30 M significantly improved the xylose yield, whereas the extent of improvement decreased to near-quantitative when further increasing acid loading. These findings shed some light on the mechanism for dilute sulfuric acid hydrolysis of corn stover. PMID:25479388

  15. Efficient production of 2,3-butanediol from corn stover hydrolysate by using a thermophilic Bacillus licheniformis strain.

    PubMed

    Li, Lixiang; Li, Kun; Wang, Kai; Chen, Chao; Gao, Chao; Ma, Cuiqing; Xu, Ping

    2014-10-01

    In this study, a thermophilic Bacillus licheniformis strain X10 was newly isolated for 2,3-butanediol (2,3-BD) production from lignocellulosic hydrolysate. Strain X10 could utilize glucose and xylose simultaneously without carbon catabolite repression. In addition, strain X10 possesses high tolerance to fermentation inhibitors including furfural, vanillin, formic acid, and acetic acid. In a fed-batch fermentation, 74.0g/L of 2,3-BD was obtained from corn stover hydrolysate, with a productivity of 2.1g/Lh and a yield of 94.6%. Thus, this thermophilic B. licheniformis strain is a candidate for the development of efficient industrial production of 2,3-BD from corn stover hydrolysate. PMID:25151068

  16. High ethanol fermentation performance of the dry dilute acid pretreated corn stover by an evolutionarily adapted Saccharomyces cerevisiae strain.

    PubMed

    Qureshi, Abdul Sattar; Zhang, Jian; Bao, Jie

    2015-01-01

    Ethanol fermentation was investigated at the high solids content of the dry dilute sulfuric acid pretreated corn stover feedstock using an evolutionary adapted Saccharomyces cerevisiae DQ1 strain. The evolutionary adaptation was conducted by successively transferring the S. cerevisiae DQ1 cells into the inhibitors containing corn stover hydrolysate every 12h and finally a stable yeast strain was obtained after 65 days' continuous adaptation. The ethanol fermentation performance using the adapted strain was significantly improved with the high ethanol titer of 71.40 g/L and the high yield of 80.34% in the simultaneous saccharification and fermentation (SSF) at 30% solids content. No wastewater was generated from pretreatment to fermentation steps. The results were compared with the published cellulosic ethanol fermentation cases, and the obvious advantages of the present work were demonstrated not only at the high ethanol titer and yield, but also the significant reduction of wastewater generation and potential cost reduction. PMID:25930238

  17. Optimization of alkaline sulfite pretreatment and comparative study with sodium hydroxide pretreatment for improving enzymatic digestibility of corn stover.

    PubMed

    Liu, Huan; Pang, Bo; Wang, Haisong; Li, Haiming; Lu, Jie; Niu, Meihong

    2015-04-01

    In this study, alkaline sulfite pretreatment of corn stover was optimized. The influences of pretreatments on solid yield, delignification, and carbohydrate recovery under different pretreatment conditions and subsequent enzymatic hydrolysis were investigated. The effect of pretreatment was evaluated by enzymatic hydrolysis efficiency and the total sugar yield. The optimum pretreatment conditions were obtained, as follows: the total titratable alkali (TTA) of 12%, liquid/solid ratio of 6:1, temperature of 140 °C, and holding time of 20 min. Under those conditions, the solid yield was 55.24%, and the removal of lignin was 82.68%. Enzymatic hydrolysis rates of glucan and xylan for pretreated corn stover were 85.38% and 70.36%, and the total sugar yield was 74.73% at cellulase loading of 20 FPU/g and β-glucosidase loading of 10 IU/g for 48 h. Compared with sodium hydroxide pretreatment with the same amount of total titratable alkali, the total sugar yield was raised by about 10.43%. Additionally, the corn stover pretreated under the optimum pretreatment conditions was beaten by PFI at 1500 revolutions. After beating, enzymatic hydrolysis rates of glucan and xylan were 89.74% and 74.06%, and the total sugar yield was 78.58% at the same enzymatic hydrolysis conditions. Compared with 1500 rpm of PFI beating after sodium pretreatment with the same amount of total titratable alkali, the total sugar yield was raised by about 14.05%. PMID:25773993

  18. Improving Biomethane Production and Mass Bioconversion of Corn Stover Anaerobic Digestion by Adding NaOH Pretreatment and Trace Elements

    PubMed Central

    Liu, ChunMei; Yuan, HaiRong; Zou, DeXun; Liu, YanPing; Zhu, BaoNing; Li, XiuJin

    2015-01-01

    This research applied sodium hydroxide (NaOH) pretreatment and trace elements to improve biomethane production when using corn stover for anaerobic digestion. Full-factor experimental tests identified the best combination of trace elements with the NaOH pretreatment, indicating that the best combination was with 1.0, 0.4, and 0.4 mg·L−1·d−1 of elements Fe, Co, and Ni, respectively. The cumulative biomethane production adding NaOH pretreatment and trace elements was 11,367 mL; total solid bioconversion rate was 55.7%, which was 41.8%–62.2% higher than with NaOH-pretreatment alone and 22.2%–56.3% higher than with untreated corn stover. The best combination was obtained 5–9 days shorter than T90 and maintained good system operation stability. Only a fraction of the trace elements in the best combination was present in the resulting solution; more than 85% of the total amounts added were transferred into the solid fraction. Adding 0.897 g of Fe, 0.389 g of Co, and 0.349 g of Ni satisfied anaerobic digestion needs and enhanced biological activity at the beginning of the operation. The results showed that NaOH pretreatment and adding trace elements improve corn stover biodegradability and enhance biomethane production. PMID:26137469

  19. Improving Biomethane Production and Mass Bioconversion of Corn Stover Anaerobic Digestion by Adding NaOH Pretreatment and Trace Elements.

    PubMed

    Liu, ChunMei; Yuan, HaiRong; Zou, DeXun; Liu, YanPing; Zhu, BaoNing; Li, XiuJin

    2015-01-01

    This research applied sodium hydroxide (NaOH) pretreatment and trace elements to improve biomethane production when using corn stover for anaerobic digestion. Full-factor experimental tests identified the best combination of trace elements with the NaOH pretreatment, indicating that the best combination was with 1.0, 0.4, and 0.4 mg·L(-1)·d(-1) of elements Fe, Co, and Ni, respectively. The cumulative biomethane production adding NaOH pretreatment and trace elements was 11,367 mL; total solid bioconversion rate was 55.7%, which was 41.8%-62.2% higher than with NaOH-pretreatment alone and 22.2%-56.3% higher than with untreated corn stover. The best combination was obtained 5-9 days shorter than T90 and maintained good system operation stability. Only a fraction of the trace elements in the best combination was present in the resulting solution; more than 85% of the total amounts added were transferred into the solid fraction. Adding 0.897 g of Fe, 0.389 g of Co, and 0.349 g of Ni satisfied anaerobic digestion needs and enhanced biological activity at the beginning of the operation. The results showed that NaOH pretreatment and adding trace elements improve corn stover biodegradability and enhance biomethane production. PMID:26137469

  20. Effect of poultry litter biochar on Saccharomyces cerevisiae growth and ethanol production from steam-exploded poplar and corn stover

    NASA Astrophysics Data System (ADS)

    Diallo, Oumou

    The use of ethanol produced from lignocellulosic biomass for transportation fuel offers solutions in reducing environmental emission and the use of non-renewable fuels. However, lignocellulosic ethanol production is still hampered by economic and technical obstacles. For instance, the inhibitory effect of toxic compounds produced during biomass pretreatment was reported to inhibit the fermenting microorganisms, hence there was a decrease in ethanol yield and productivity. Thus, there is a need to improve the bioconversion of lignocellulosic biomass to ethanol in order to promote its commercialization. The research reported here investigated the use of poultry litter biochar to improve the ethanol production from steam-exploded poplar and corn stover. The effect of poultry litter biochar was first studied on Saccharomyces cerevisiae ATCC 204508/S288C growth, and second on the enzyme hydrolysis and fermentation of two steam-exploded biomasses: (poplar and corn stover). The third part of the study investigated optimal process parameters (biochar loading, biomass loading, and enzyme loading) on the reducing sugars production, and ethanol yield from steam-exploded corn stover. In this study, it has been shown that poultry litter biochar improved the S. cerevisiae growth and ethanol productivity; therefore poultry litter biochar could potentially be used to improve the ethanol production from steam-exploded lignocellulosic biomass.

  1. Characterization of pilot-scale dilute acid pretreatment performance using deacetylated corn stover

    PubMed Central

    2014-01-01

    Background Dilute acid pretreatment is a promising process technology for the deconstruction of low-lignin lignocellulosic biomass, capable of producing high yields of hemicellulosic sugars and enhancing enzymatic yields of glucose as part of a biomass-to-biofuels process. However, while it has been extensively studied, most work has historically been conducted at relatively high acid concentrations of 1 - 4% (weight/weight). Reducing the effective acid loading in pretreatment has the potential to reduce chemical costs both for pretreatment and subsequent neutralization. Additionally, if acid loadings are sufficiently low, capital requirements associated with reactor construction may be significantly reduced due to the relaxation of requirements for exotic alloys. Despite these benefits, past efforts have had difficulty obtaining high process yields at low acid loadings without supplementation of additional unit operations, such as mechanical refining. Results Recently, we optimized the dilute acid pretreatment of deacetylated corn stover at low acid loadings in a 1-ton per day horizontal pretreatment reactor. This effort included more than 25 pilot-scale pretreatment experiments executed at reactor temperatures ranging from 150 – 170°C, residence times of 10 – 20 minutes and hydrolyzer sulfuric acid concentrations between 0.15 – 0.30% (weight/weight). In addition to characterizing the process yields achieved across the reaction space, the optimization identified a pretreatment reaction condition that achieved total xylose yields from pretreatment of 73.5% ± 1.5% with greater than 97% xylan component balance closure across a series of five runs at the same condition. Feedstock reactivity at this reaction condition after bench-scale high solids enzymatic hydrolysis was 77%, prior to the inclusion of any additional conversion that may occur during subsequent fermentation. Conclusions This study effectively characterized a range of pretreatment reaction

  2. Ash reduction strategies in corn stover facilitated by anatomical and size fractionation

    DOE PAGESBeta

    Lacey, Jeffrey A.; Emerson, Rachel M.; Thompson, David N.; Westover, Tyler L.

    2016-04-22

    There is growing interest internationally to produce fuels from renewable biomass resources. Inorganic components of biomass feedstocks, referred to collectively as ash, damage equipment and decrease yields in thermal conversion processes, and decrease feedstock value for biochemical conversion processes. Decreasing the ash content of feedstocks improves conversion efficiency and lowers process costs. Because physiological ash is unevenly distributed in the plant, mechanical processes can be used to separate fractions of the plant based on ash content. This study focuses on the ash separation that can be achieved by separating corn stover by particle size and anatomical fraction. Baled corn stovermore » was hand-separated into anatomical fractions, ground to <19.1 mm, and size separated using six sieves ranging from 9.5 to 0.150 mm. Size fractions were analyzed for total ash content and ash composition. Particle size distributions observed for the anatomical fractions varied considerably. Cob particles were primarily 2.0 mm or greater, while most of the sheath and husk particles were 2.0 mm and smaller. Particles of leaves greater than 0.6 mm contained the greatest amount of total ash, ranging from approximately 8 to 13% dry weight of the total original material, while the fractions with particles smaller than 0.6 mm contained less than 2% of the total ash of the original material. As a result, based on the overall ash content and the elemental ash, specific anatomical and size fractions can be separated to optimize the feedstocks being delivered to biofuels conversion processes and minimize the need for more expensive ash reduction treatments.« less

  3. Soaking pretreatment of corn stover for bioethanol production followed by anaerobic digestion process.

    PubMed

    Zuo, Zhuang; Tian, Shen; Chen, Zebing; Li, Jia; Yang, Xiushan

    2012-08-01

    The production of ethanol and methane from corn stover (CS) was investigated in a biorefinery process. Initially, a novel soaking pretreatment (NaOH and aqueous-ammonia) for CS was developed to remove lignin, swell the biomass, and improve enzymatic digestibility. Based on the sugar yield during enzymatic hydrolysis, the optimal pretreatment conditions were 1 % NaOH+8 % NH(4)OH, 50°C, 48 h, with a solid-to-liquid ratio 1:10. The results demonstrated that soaking pretreatment removed 63.6 % lignin while reserving most of the carbohydrates. After enzymatic hydrolysis, the yields of glucose and xylose were 78.5 % and 69.3 %, respectively. The simultaneous saccharification and fermentation of pretreated CS using Pichia stipitis resulted in an ethanol concentration of 36.1 g/L, corresponding only to 63.3 % of the theoretical maximum. In order to simplify the process and reduce the capital cost, the liquid fraction of the pretreatment was used to re-soak new CS. For methane production, the re-soaked CS and the residues of SSF were anaerobically digested for 120 days. Fifteen grams CS were converted to 1.9 g of ethanol and 1337.3 mL of methane in the entire process. PMID:22669688

  4. Lactic Acid Production from Pretreated Hydrolysates of Corn Stover by a Newly Developed Bacillus coagulans Strain.

    PubMed

    Jiang, Ting; Qiao, Hui; Zheng, Zhaojuan; Chu, Qiulu; Li, Xin; Yong, Qiang; Ouyang, Jia

    2016-01-01

    An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP) mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH) of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH), condensed acid-catalyzed liquid hot water hydrolysate (CALH) and condensed acid-catalyzed sulfite hydrolysate (CASH) as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF), vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal) on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates. PMID:26863012

  5. Blending municipal solid waste with corn stover for sugar production using ionic liquid process

    SciTech Connect

    Sun, Ning; Xu, Feng; Sathitsuksanoh, Noppadon; Thompson, Vicki S.; Cafferty, Kara; Li, Chenlin; Tanjore, Deepti; Narani, Akash; Pray, Todd R.; Simmons, Blake A.; Singh, Seema

    2015-06-01

    Municipal solid waste (MSW) represents an attractive cellulosic resource for sustainable fuel production because of its abundance and its low or perhaps negative cost. However, the significant heterogeneity and toxic contaminants are barriers to efficient conversion to ethanol and other products. In this study, we generated MSW paper mix, blended with corn stover (CS), and have shown that both MSW paper mix alone and MSW/CS blends can be efficiently pretreated in certain ionic liquids (ILs) with high yields of fermentable sugars. After pretreatment in 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]), over 80% glucose has been released with enzymatic saccharification. We have also applied an enzyme free process by adding mineral acid and water directly into the IL/biomass slurry to induce hydrolysis. With the acidolysis process in the IL 1-ethyl-3-methylimidazolium chloride ([C2C1Im]Cl), up to 80% glucose and 90% xylose are released for MSW. The results indicate the feasibility of incorporating MSW as a robust blending agent for biorefineries.

  6. High temperature pre-digestion of corn stover biomass for improved product yields

    SciTech Connect

    Brunecky, Roman; Hobdey, Sarah E.; Taylor, Larry E.; Tao, Ling; Tucker, Melvin P.; Himmel, Michael E.; Decker, Stephen R.

    2014-12-03

    Introduction: The efficient conversion of lignocellulosic feedstocks remains a key step in the commercialization of biofuels. One of the barriers to cost-effective conversion of lignocellulosic biomass to sugars remains the enzymatic saccharification process step. Here, we describe a novel hybrid processing approach comprising enzymatic pre-digestion with newly characterized hyperthermophilic enzyme cocktails followed by conventional saccharification with commercial enzyme preparations. Dilute acid pretreated corn stover was subjected to this new procedure to test its efficacy. Thermal tolerant enzymes from Acidothermus cellulolyticus and Caldicellulosiruptor bescii were used to pre-digest pretreated biomass at elevated temperatures prior to saccharification by the commercial cellulase formulation. Results: We report that pre-digestion of biomass with these enzymes at elevated temperatures prior to addition of the commercial cellulase formulation increased conversion rates and yields when compared to commercial cellulase formulation alone under low solids conditions. In conclusion, Our results demonstrating improvements in rates and yields of conversion point the way forward for hybrid biomass conversion schemes utilizing catalytic amounts of hyperthermophilic enzymes.

  7. Response Surface Analysis of Elemental Composition and Energy Properties of Corn Stover During Torrefaction

    SciTech Connect

    Jaya Shankar Tumuluru; Richard D. Boardman; Christopher T. Wright

    2012-02-01

    This research studied the effects of torrefaction temperature (250-250 C) and time (30-120 minutes) on elemental composition and energy properties changes in corn stover. Torrefied material was analyzed for moisture content, moisture-free carbon (%), hydrogen (%), nitrogen (%), sulfur (%), and higher heating value (MJ/kg). Results at 350 C and 120 minutes indicated a steep decrease in moisture content to a final value of about 1.48% - a reduction of about 69%. With respect to carbon content, the increase was about 23%, while hydrogen and sulfur content decreased by about 46.82% and 66.6%, respectively. The hydrogen-to-carbon ratio decreased as torrefaction temperature and time increased, with the lowest value of 0.6 observed at 350 C and 120 minutes. Higher heating value measured at 350 C and 60 minutes increased by about 22% and the maximum degree of carbonization observed was about 1.21. Further, the regression models developed for chemical composition in terms of torrefaction temperature and time adequately described the process with coefficient of determination values (R2) in the range of 0.92-0.99 for the elemental composition and energy properties studied. Response surface plots indicated that increasing both torrefaction temperature and time resulted in decreased moisture content, hydrogen content, and the hydrogen to-carbon ratio, and increased carbon content and higher heating value. This effect was more significant at torrefaction temperatures and times >280 C and >30 minutes.

  8. Biobutanol production from corn stover hydrolysate pretreated with recycled ionic liquid by Clostridium saccharobutylicum DSM 13864.

    PubMed

    Ding, Ji-Cai; Xu, Guo-Chao; Han, Rui-Zhi; Ni, Ye

    2016-01-01

    In this study, corn stover (CS) hydrolysates, pretreated by fresh and recycled ionic liquid (IL) [Bmim][Cl], were utilized in butanol fermentation by Clostridium saccharobutylicum DSM 13864. An efficient CS pretreatment procedure using [Bmim][Cl] was developed, giving a glucose concentration of 18.7 g L(-1) using ten times recycled [Bmim][Cl], representing about 77% of that produced with fresh IL (24.2 g L(-1)). Fermentation of hydrolysate I (pretreated by fresh IL) resulted in 7.4 g L(-1) butanol with a yield of 0.21 g g total-sugar(-1) and a productivity of 0.11 g L(-1)h(-1), while 7.9 g L(-1) butanol was achieved in fermentation using hydrolysate II (pretreated by ten times reused IL) with similar levels of acetone and ethanol, as well as yield and productivity. This study provides evidence for the efficient utilization of IL in CS pretreatment for biobutanol fermentation. PMID:26318847

  9. Physical and Chemical Properties of Bio-Oils From Microwave Pyrolysis of Corn Stover

    NASA Astrophysics Data System (ADS)

    Yu, Fei; Deng, Shaobo; Chen, Paul; Liu, Yuhuan; Wan, Yiqin; Olson, Andrew; Kittelson, David; Ruan, Roger

    This study was aimed to understand the physical and chemical properties of pyrolytic bio-oils produced from microwave pyrolysis of corn stover regarding their potential use as gas turbine and home heating fuels. The ash content, solids content, pH, heating value, minerals, elemental ratio, moisture content, and viscosity of the bio-oils were determined. The water content was approx 15.2 wt%, solids content 0.22 wt%, alkali metal content 12 parts per million, dynamic viscosity 185 mPa·s at 40°C, and gross high heating value 17.5 MJ/kg for a typical bio-oil produced. Our aging tests showed that the viscosity and water content increased and phase separation occurred during the storage at different temperatures. Adding methanol and/or ethanol to the bio-oils reduced the viscosity and slowed down the increase in viscosity and water content during the storage. Blending of methanol or ethanol with the bio-oils may be a simple and cost-effective approach to making the pyrolytic bio-oils into a stable gas turbine or home heating fuels.

  10. Physical and chemical properties of bio-oils from microwave pyrolysis of corn stover.

    PubMed

    Yu, Fei; Deng, Shaobo; Chen, Paul; Liu, Yuhuan; Wan, Yiqin; Olson, Andrew; Kittelson, David; Ruan, Roger

    2007-04-01

    This study was aimed to understand the physical and chemical properties of pyrolytic bio-oils produced from microwave pyrolysis of corn stover regarding their potential use as gas turbine and home heating fuels. The ash content, solids content, pH, heating value, minerals, elemental ratio, moisture content, and viscosity of the bio-oils were determined. The water content was approx 15.2 wt%, solids content 0.22 wt%, alkali metal content 12 parts per million, dynamic viscosity 185 mPa.s at 40 degrees C, and gross high heating value 17.5 MJ/kg for a typical bio-oil produced. Our aging tests showed that the viscosity and water content increased and phase separation occurred during the storage at different temperatures. Adding methanol and/or ethanol to the bio-oils reduced the viscosity and slowed down the increase in viscosity and water content during the storage. Blending of methanol or ethanol with the bio-oils may be a simple and cost-effective approach to making the pyrolytic bio-oils into a stable gas turbine or home heating fuels. PMID:18478448

  11. Strategies to achieve high-solids enzymatic hydrolysis of dilute-acid pretreated corn stover.

    PubMed

    Geng, Wenhui; Jin, Yongcan; Jameel, Hasan; Park, Sunkyu

    2015-01-01

    Three strategies were presented to achieve high solids loading while maximizing carbohydrate conversion, which are fed-batch, splitting/thickening, and clarifier processes. Enzymatic hydrolysis was performed at water insoluble solids (WIS) of 15% using washed dilute-acid pretreated corn stover. The carbohydrate concentration increased from 31.8 to 99.3g/L when the insoluble solids content increased from 5% to 15% WIS, while the final carbohydrate conversion was decreased from 78.4% to 73.2%. For the fed-batch process, a carbohydrate conversion efficiency of 76.8% was achieved when solid was split into 60:20:20 ratio, with all enzymes added first. For the splitting/thickening process, a carbohydrate conversion of 76.5% was realized when the filtrate was recycled to simulate a steady-state process. Lastly, the clarifier process was evaluated and the highest carbohydrate conversion of 81.4% was achieved. All of these results suggests the possibility of enzymatic hydrolysis at high solids to make the overall conversion cost-competitive. PMID:25836373

  12. Comparison of different pretreatments for the production of bioethanol and biomethane from corn stover and switchgrass.

    PubMed

    Papa, G; Rodriguez, S; George, A; Schievano, A; Orzi, V; Sale, K L; Singh, S; Adani, F; Simmons, B A

    2015-05-01

    In this study the efficiency of mild ionic liquid (IL) pretreatment and pressurized hot water (PHW) is evaluated and compared in terms of bioethanol and biomethane yields, with corn stover (CS) and switchgrass (SG) as model bioenergy crops. Both feedstocks pretreated with the IL 1-ethyl-3-methylimidazolium acetate [C2C1Im][OAc] at 100°C for 3h exhibited lower glucose yield that those treated with harsher pretreatment conditions previously used. Compared to PHW, IL pretreatment demonstrated higher bioethanol yields; moreover IL pretreatment enhanced biomethane production. Taking into consideration both bioethanol and biomethane productions, results indicated that when using IL pretreatment, the total energy produced per kg of total solids was higher compared to untreated biomasses. Specifically energy produced from CS and SG was +18.6% and +34.5% respectively, as compared to those obtained by hot water treatment, i.e. +2.3% and +23.4% for CS and SG, respectively. PMID:25725408

  13. Blending municipal solid waste with corn stover for sugar production using ionic liquid process.

    PubMed

    Sun, Ning; Xu, Feng; Sathitsuksanoh, Noppadon; Thompson, Vicki S; Cafferty, Kara; Li, Chenlin; Tanjore, Deepti; Narani, Akash; Pray, Todd R; Simmons, Blake A; Singh, Seema

    2015-06-01

    Municipal solid waste (MSW) represents an attractive cellulosic resource for sustainable fuel production. However, its heterogeneity is the major barrier to efficient conversion to biofuels. MSW paper mix was generated and blended with corn stover (CS). It has been shown that both of them can be efficiently pretreated in certain ionic liquids (ILs) with high yields of fermentable sugars. After pretreatment in 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]), over 80% glucose has been released with enzymatic saccharification. We have also applied an enzyme-free process by adding mineral acid and water directly into the IL/biomass slurry to induce hydrolysis. With the acidolysis process in 1-ethyl-3-methylimidazolium chloride ([C2C1Im]Cl), up to 80% glucose and 90% xylose are released. There is a correlation between the viscosity profile and hydrolysis efficiency; low viscosity of the hydrolysate generally corresponds to high sugar yields. Overall, the results indicate the feasibility of incorporating MSW as a robust blending agent for biorefineries. PMID:25817030

  14. Drought effects on composition and yield for corn stover, mixed grasses, and Miscanthus as bioenergy feedstocks

    SciTech Connect

    Rachel Emerson; Amber Hoover; Allison Ray; Jeffrey Lacey; Marnie Cortez; Courtney Payne; Doug Karlen; Stuart Birrell; David Laird; Robert Kallenbach; Josh Egenolf; Matthew Sousek; Thomas Voigt

    2014-11-01

    Drought conditions in 2012 were some of the most severe reported in the United States. It is necessary to explore the effects of drought on the quality attributes of current and potential bioenergy feedstocks. Compositional analysis data for corn stover, Miscanthus, and CRP grasses from one or more locations for years 2010 (normal precipitation levels) and 2012 (a known severe drought year nationally) was collected. Results & discussion: The general trend for samples that experienced drought was an increase in extractives and a decrease in structural sugars and lignin. The TEY yields were calculated to determine the drought effects on ethanol production. All three feedstocks had a decrease of 12-14% in TEY when only decreases of carbohydrate content was analyzed. When looking at the compounded effect of both carbohydrate content and the decreases in dry matter loss for each feedstock there was a TEY decrease of 25%-59%. Conclusion: Drought had a significant impact on the quality of all three bioenergy crops. In all cases where drought was experienced both the quality of the feedstock and the yield decreased. These drought induced effects could have significant economic impacts on biorefineries.

  15. A low-cost solid–liquid separation process for enzymatically hydrolyzed corn stover slurries

    DOE PAGESBeta

    Sievers, David A.; Lischeske, James J.; Biddy, Mary J.; Stickel, Jonathan J.

    2015-07-01

    Solid-liquid separation of intermediate process slurries is required in some process configurations for the conversion of lignocellulosic biomass to transportation fuels. Thermochemically pretreated and enzymatically hydrolyzed corn stover slurries have proven difficult to filter due to formation of very low permeability cakes that are rich in lignin. Treatment of two different slurries with polyelectrolyte flocculant was demonstrated to increase mean particle size and filterability. Filtration flux was greatly improved, and thus scaled filter unit capacity was increased approximately 40-fold compared with unflocculated slurry. Although additional costs were accrued using polyelectrolyte, techno-economic analysis revealed that the increase in filter capacity significantlymore » reduced overall production costs. Fuel production cost at 95% sugar recovery was reduced by $1.35 US per gallon gasoline equivalent for dilute-acid pretreated and enzymatically hydrolyzed slurries and $3.40 for slurries produced using an additional alkaline de-acetylation preprocessing step that is even more difficult to natively filter.« less

  16. High temperature pre-digestion of corn stover biomass for improved product yields

    DOE PAGESBeta

    Brunecky, Roman; Hobdey, Sarah E.; Taylor, Larry E.; Tao, Ling; Tucker, Melvin P.; Himmel, Michael E.; Decker, Stephen R.

    2014-12-03

    Introduction: The efficient conversion of lignocellulosic feedstocks remains a key step in the commercialization of biofuels. One of the barriers to cost-effective conversion of lignocellulosic biomass to sugars remains the enzymatic saccharification process step. Here, we describe a novel hybrid processing approach comprising enzymatic pre-digestion with newly characterized hyperthermophilic enzyme cocktails followed by conventional saccharification with commercial enzyme preparations. Dilute acid pretreated corn stover was subjected to this new procedure to test its efficacy. Thermal tolerant enzymes from Acidothermus cellulolyticus and Caldicellulosiruptor bescii were used to pre-digest pretreated biomass at elevated temperatures prior to saccharification by the commercial cellulase formulation.more » Results: We report that pre-digestion of biomass with these enzymes at elevated temperatures prior to addition of the commercial cellulase formulation increased conversion rates and yields when compared to commercial cellulase formulation alone under low solids conditions. In conclusion, Our results demonstrating improvements in rates and yields of conversion point the way forward for hybrid biomass conversion schemes utilizing catalytic amounts of hyperthermophilic enzymes.« less

  17. Lactic Acid Production from Pretreated Hydrolysates of Corn Stover by a Newly Developed Bacillus coagulans Strain

    PubMed Central

    Jiang, Ting; Qiao, Hui; Zheng, Zhaojuan; Chu, Qiulu; Li, Xin; Yong, Qiang; Ouyang, Jia

    2016-01-01

    An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP) mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH) of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH), condensed acid-catalyzed liquid hot water hydrolysate (CALH) and condensed acid-catalyzed sulfite hydrolysate (CASH) as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF), vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal) on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates. PMID:26863012

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

    PubMed Central

    2014-01-01

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

  19. Improvement of sugar yields from corn stover using sequential hot water pretreatment and disk milling.

    PubMed

    Kim, Sun Min; Dien, Bruce S; Tumbleson, M E; Rausch, Kent D; Singh, Vijay

    2016-09-01

    Efficient pretreatment is essential for economic conversion of lignocellulosic feedstocks into monosaccharides for biofuel production. To realize high sugar yields with low inhibitor concentrations, hot water or dilute acid pretreatment followed by disk milling is proposed. Corn stover at 20% solids was pretreated with hot water at 160-200°C for 4-8min with and without subsequent milling. Hot water pretreatment and disk milling acted synergistically to improve glucose and xylose yields by 89% and 134%, respectively, compared to hot water pretreatment alone. Hot water pretreated (180°C for 4min) and milled samples had the highest glucose and xylose yields among all hot water pretreated and milled samples, which were comparable to samples pretreated with 0.55% dilute acid at 160°C for 4min. However, samples pretreated with 1% dilute acid at 150°C for 4min and disk milled had the highest observed glucose (87.3%) and xylose yields (83.4%). PMID:27289063

  20. Optimization and economic evaluation of industrial gas production and combined heat and power generation from gasification of corn stover and distillers grains.

    PubMed

    Kumar, Ajay; Demirel, Yasar; Jones, David D; Hanna, Milford A

    2010-05-01

    Thermochemical gasification is one of the most promising technologies for converting biomass into power, fuels and chemicals. The objectives of this study were to maximize the net energy efficiency for biomass gasification, and to estimate the cost of producing industrial gas and combined heat and power (CHP) at a feedrate of 2000kg/h. Aspen Plus-based model for gasification was combined with a CHP generation model, and optimized using corn stover and dried distillers grains with solubles (DDGS) as the biomass feedstocks. The cold gas efficiencies for gas production were 57% and 52%, respectively, for corn stover and DDGS. The selling price of gas was estimated to be $11.49 and $13.08/GJ, respectively, for corn stover and DDGS. For CHP generation, the electrical and net efficiencies were as high as 37% and 88%, respectively, for corn stover and 34% and 78%, respectively, for DDGS. The selling price of electricity was estimated to be $0.1351 and $0.1287/kWh for corn stover and DDGS, respectively. Overall, high net energy efficiencies for gas and CHP production from biomass gasification can be achieved with optimized processing conditions. However, the economical feasibility of these conversion processes will depend on the relative local prices of fossil fuels. PMID:20096571

  1. KNIFE MILL COMMINUTION ENERGY ANALYSIS OF SWITCHGRASS, WHEAT STRAW, AND CORN STOVER AND CHARACTERIZATION OF PARTICLE SIZE DISTRIBUTIONS

    SciTech Connect

    Bitra, V.S.P.; Womac, A.R.; Sokhansanj, Shahabaddine; Igathinathane, C.

    2010-01-01

    Biomass preprocessing and pretreatment technologies such as size reduction and chemical preconditioning are aimed at reducing the cost of ethanol production from lignocellulosic biomass. Size reduction is an energy-intensive biomass preprocessing unit operation. In this study, switchgrass, wheat straw, and corn stover were chopped in an instrumented knife mill to evaluate size reduction energy and corresponding particle size distribution as determined with a standard forage sieve analyzer. Direct mechanical power inputs were determined using a dedicated data acquisition system for knife mill screen openings from 12.7 to 50.8 mm, rotor speeds between 250 and 500 rpm, and mass feed rates from 1 to 11 kg/min. A speed of 250 rpm gave optimum performance of the mill. Optimum feed rates for 25.4 mm screen and 250 rpm were 7.6, 5.8, and 4.5 kg/min for switchgrass, wheat straw, and corn stover, respectively. Total specific energy (MJ/Mg) was defined as the size reduction energy required to operate the knife mill plus that imparted to the biomass. Effective specific energy was defined as the energy imparted to the biomass. For these conditions, total specific energies were 27.3, 37.9, and 31.9 MJ/Mg and effective specific energies were 10.1, 15.5, and 3.2 MJ/Mg for switchgrass, wheat straw, and corn stover, respectively. These results demonstrated that biomass selection affects the size reduction energy, even for biomass with similar features. Second-order polynomial equations for the total specific energy requirement fitted well (R2 > 0.95) as a function of knife mill screen size, mass feed rate, and speed for biomass materials tested. The Rosin-Rammler equation fitted the cumulative undersize mass of switchgrass, wheat straw, and corn stover chop passed through ASABE sieves with high R2 (>0.983). Knife mill chopping of switchgrass, wheat straw, and corn stover resulted in particle size distributions classified as 'well-graded strongly fine-skewed mesokurtic', 'well

  2. Hydrocarbon Liquid Production via Catalytic Hydroprocessing of Phenolic Oils Fractionated from Fast Pyrolysis of Red Oak and Corn Stover

    SciTech Connect

    Elliott, Douglas C.; Wang, Huamin; Rover, Majorie; Whitmer, Lysle; Smith, Ryan; Brown, Robert C.

    2015-04-13

    Phenolic oils were produced from fast pyrolysis of two different biomass feedstocks, red oak and corn stover and evaluated in hydroprocessing tests for production of liquid hydrocarbon products. The phenolic oils were produced with a bio-oil fractionating process in combination with a simple water wash of the heavy ends from the fractionating process. Phenolic oils derived from the pyrolysis of red oak and corn stover were recovered with yields (wet biomass basis) of 28.7 wt% and 14.9 wt%, respectively, and 54.3% and 58.6% on a carbon basis. Both precious metal catalysts and sulfided base metal catalyst were evaluated for hydrotreating the phenolic oils, as an extrapolation from whole bio-oil hydrotreatment. They were effective in removing heteroatoms with carbon yields as high as 81% (unadjusted for the 90% carbon balance). There was nearly complete heteroatom removal with residual O of only 0.4% to 5%, while N and S were reduced to less than 0.05%. Use of the precious metal catalysts resulted in more saturated products less completely hydrotreated compared to the sulfided base metal catalyst, which was operated at higher temperature. The liquid product was 42-52% gasoline range molecules and about 43% diesel range molecules. Particulate matter in the phenolic oils complicated operation of the reactors, causing plugging in the fixed-beds especially for the corn stover phenolic oil. This difficulty contrasts with the catalyst bed fouling and plugging, which is typically seen with hydrotreatment of whole bio-oil. This problem was substantially alleviated by filtering the phenolic oils before hydrotreating. More thorough washing of the phenolic oils during their preparation from the heavy ends of bio-oil or on-line filtration of pyrolysis vapors to remove particulate matter before condensation of the bio-oil fractions is recommended.

  3. Hydrocarbon Liquid Production via Catalytic Hydroprocessing of Phenolic Oils Fractionated from Fast Pyrolysis of Red Oak and Corn Stover

    DOE PAGESBeta

    Elliott, Douglas C.; Wang, Huamin; Rover, Majorie; Whitmer, Lysle; Smith, Ryan; Brown, Robert C.

    2015-04-13

    Phenolic oils were produced from fast pyrolysis of two different biomass feedstocks, red oak and corn stover and evaluated in hydroprocessing tests for production of liquid hydrocarbon products. The phenolic oils were produced with a bio-oil fractionating process in combination with a simple water wash of the heavy ends from the fractionating process. Phenolic oils derived from the pyrolysis of red oak and corn stover were recovered with yields (wet biomass basis) of 28.7 wt% and 14.9 wt%, respectively, and 54.3% and 58.6% on a carbon basis. Both precious metal catalysts and sulfided base metal catalyst were evaluated for hydrotreatingmore » the phenolic oils, as an extrapolation from whole bio-oil hydrotreatment. They were effective in removing heteroatoms with carbon yields as high as 81% (unadjusted for the 90% carbon balance). There was nearly complete heteroatom removal with residual O of only 0.4% to 5%, while N and S were reduced to less than 0.05%. Use of the precious metal catalysts resulted in more saturated products less completely hydrotreated compared to the sulfided base metal catalyst, which was operated at higher temperature. The liquid product was 42-52% gasoline range molecules and about 43% diesel range molecules. Particulate matter in the phenolic oils complicated operation of the reactors, causing plugging in the fixed-beds especially for the corn stover phenolic oil. This difficulty contrasts with the catalyst bed fouling and plugging, which is typically seen with hydrotreatment of whole bio-oil. This problem was substantially alleviated by filtering the phenolic oils before hydrotreating. More thorough washing of the phenolic oils during their preparation from the heavy ends of bio-oil or on-line filtration of pyrolysis vapors to remove particulate matter before condensation of the bio-oil fractions is recommended.« less

  4. Evaluation of Thermal Evolution Profiles and Estimation of Kinetic Parameters for Pyrolysis of Coal/Corn Stover Blends Using Thermogravimetric Analysis

    DOE PAGESBeta

    Bhagavatula, Abhijit; Huffman, Gerald; Shah, Naresh; Honaker, Rick

    2014-01-01

    The thermal evolution profiles and kinetic parameters for the pyrolysis of two Montana coals (DECS-38 subbituminous coal and DECS-25 lignite coal), one biomass sample (corn stover), and their blends (10%, 20%, and 30% by weight of corn stover) have been investigated at a heating rate of 5°C/min in an inert nitrogen atmosphere, using thermogravimetric analysis. The thermal evolution profiles of subbituminous coal and lignite coal display only one major peak over a wide temperature distribution, ~152–814°C and ~175–818°C, respectively, whereas the thermal decomposition profile for corn stover falls in a much narrower band than that of the coals, ~226–608°C. Themore » nonlinearity in the evolution of volatile matter with increasing percentage of corn stover in the blends verifies the possibility of synergistic behavior in the blends with subbituminous coal where deviations from the predicted yield ranging between 2% and 7% were observed whereas very little deviations (1%–3%) from predicted yield were observed in blends with lignite indicating no significant interactions with corn stover. In addition, a single first-order reaction model using the Coats-Redfern approximation was utilized to predict the kinetic parameters of the pyrolysis reaction. The kinetic analysis indicated that each thermal evolution profile may be represented as a single first-order reaction. Three temperature regimes were identified for each of the coals while corn stover and the blends were analyzed using two and four temperature regimes, respectively.« less

  5. Influence of Airflow on Laboratory Storage of High Moisture Corn Stover

    SciTech Connect

    Lynn M. Wendt; Ian J. Bonner; Amber N. Hoover; Rachel M. Emerson; William A. Smith

    2014-04-01

    Storing high moisture biomass for bioenergy use is a reality in many areas of the country where wet harvest conditions and environmental factors prevent dry storage from being feasible. Aerobic storage of high moisture biomass leads to microbial degradation and self-heating, but oxygen limitation can aid in material preservation. To understand the influence of oxygen presence on high moisture biomass (50 %, wet basis), three airflow rates were tested on corn stover stored in laboratory reactors. Temperature, carbon dioxide production, dry matter loss, chemical composition, fungal abundance, pH, and organic acids were used to monitor the effects of airflow on storage conditions. The results of this work indicate that oxygen availability impacts both the duration of self-heating and the severity of dry matter loss. High airflow systems experienced the greatest initial rates of loss but a shortened microbially active period that limited total dry matter loss (19 %). Intermediate airflow had improved preservation in short-term storage compared to high airflow systems but accumulated the greatest dry matter loss over time (up to 27 %) as a result of an extended microbially active period. Low airflow systems displayed the best performance with the lowest rates of loss and total loss (10 %) in storage at 50 days. Total structural sugar levels of the stored material were preserved, although glucan enrichment and xylan loss were documented in the high and intermediate flow conditions. By understanding the role of oxygen availability on biomass storage performance, the requirements for high moisture storage solutions may begin to be experimentally defined.

  6. Flexible biorefinery for producing fermentation sugars, lignin and pulp from corn stover.

    PubMed

    Kadam, Kiran L; Chin, Chim Y; Brown, Lawrence W

    2008-05-01

    A new biorefining process is presented that embodies green processing and sustainable development. In the spirit of a true biorefinery, the objective is to convert agricultural residues and other biomass feedstocks into value-added products such as fuel ethanol, dissolving pulp, and lignin for resin production. The continuous biomass fractionation process yields a liquid stream rich in hemicellulosic sugars, a lignin-rich liquid stream, and a solid cellulose stream. This paper generally discusses potential applications of the three streams and specifically provides results on the evaluation of the cellulose stream from corn stover as a source of fermentation sugars and specialty pulp. Enzymatic hydrolysis of this relatively pure cellulose stream requires significantly lower enzyme loadings because of minimal enzyme deactivation from nonspecific binding to lignin. A correlation was shown to exist between lignin removal efficiency and enzymatic digestibility. The cellulose produced was also demonstrated to be a suitable replacement for hardwood pulp, especially in the top ply of a linerboard. Also, the relatively pure nature of the cellulose renders it suitable as raw material for making dissolving pulp. This pulping approach has significantly smaller environmental footprint compared to the industry-standard kraft process because no sulfur- or chlorine-containing compounds are used. Although this option needs some minimal post-processing, it produces a higher value commodity than ethanol and, unlike ethanol, does not need extensive processing such as hydrolysis or fermentation. Potential use of low-molecular weight lignin as a raw material for wood adhesive production is discussed as well as its use as cement and feed binder. As a baseline application the hemicellulosic sugars captured in the hydrolyzate liquor can be used to produce ethanol, but potential utilization of xylose for xylitol fermentation is also feasible. Markets and values of these applications are

  7. Ammonia, Total Reduced Sulfides, and Greenhouse Gases of Pine Chip and Corn Stover Bedding Packs.

    PubMed

    Spiehs, Mindy J; Brown-Brandl, Tami M; Parker, David B; Miller, Daniel N; Berry, Elaine D; Wells, James E

    2016-03-01

    Bedding materials may affect air quality in livestock facilities. Our objective in this study was to compare headspace concentrations of ammonia (NH), total reduced sulfides (TRS), carbon dioxide (CO), methane (CH), and nitrous oxide (NO) when pine wood chips ( spp.) and corn stover ( L.) were mixed in various ratios (0, 10, 20, 30, 40, 60, 80, and 100% pine chips) and used as bedding with manure. Air samples were collected from the headspace of laboratory-scaled bedded manure packs weekly for 42 d. Ammonia concentrations were highest for bedded packs containing 0, 10, and 20% pine chips (equivalent to 501.7, 502.3, and 502.3 mg m, respectively) in the bedding mixture and were lowest when at least 80% pine chips were used as bedding (447.3 and 431.0 mg m, respectively for 80 and 100% pine chip bedding). The highest NH concentrations were observed at Day 28. The highest concentration of TRS was observed when 100% pine chips were used as bedding (11.4 µg m), with high concentrations occurring between Days 7 and 14, and again at Day 35. Greenhouse gases were largely unaffected by bedding material but CH and CO concentrations increased as the bedded packs aged and NO concentrations were highly variable throughout the incubation. We conclude that a mixture of bedding material that contains 30 to 40% pine chips may be the ideal combination to reduce both NH and TRS emissions. All gas concentrations increased as the bedded packs aged, suggesting that frequent cleaning of facilities would improve air quality in the barn, regardless of bedding materials used. PMID:27065410

  8. Identification and Antimicrobial Activity Detection of Lactic Acid Bacteria Isolated from Corn Stover Silage

    PubMed Central

    Li, Dongxia; Ni, Kuikui; Pang, Huili; Wang, Yanping; Cai, Yimin; Jin, Qingsheng

    2015-01-01

    A total of 59 lactic acid bacteria (LAB) strains were isolated from corn stover silage. According to phenotypic and chemotaxonomic characteristics, 16S ribosomal DNA (rDNA) sequences and recA gene polymerase chain reaction amplification, these LAB isolates were identified as five species: Lactobacillus (L.) plantarum subsp. plantarum, Pediococcus pentosaceus, Enterococcus mundtii, Weissella cibaria and Leuconostoc pseudomesenteroides, respectively. Those strains were also screened for antimicrobial activity using a dual-culture agar plate assay. Based on excluding the effects of organic acids and hydrogen peroxide, two L. plantarum subsp. plantarum strains ZZU 203 and 204, which strongly inhibited Salmonella enterica ATCC 43971T, Micrococcus luteus ATCC 4698T and Escherichia coli ATCC 11775T were selected for further research on sensitivity of the antimicrobial substance to heat, pH and protease. Cell-free culture supernatants of the two strains exhibited strong heat stability (60 min at 100°C), but the antimicrobial activity was eliminated after treatment at 121°C for 15 min. The antimicrobial substance remained active under acidic condition (pH 2.0 to 6.0), but became inactive under neutral and alkaline condition (pH 7.0 to 9.0). In addition, the antimicrobial activities of these two strains decreased remarkably after digestion by protease K. These results preliminarily suggest that the desirable antimicrobial activity of strains ZZU 203 and 204 is the result of the production of a bacteriocin-like substance, and these two strains with antimicrobial activity could be used as silage additives to inhibit proliferation of unwanted microorganism during ensiling and preserve nutrients of silage. The nature of the antimicrobial substances is being investigated in our laboratory. PMID:25924957

  9. Improving a recombinant Zymomonas mobilis strain 8b through continuous adaptation on dilute acid pretreated corn stover hydrolysate

    DOE PAGESBeta

    Mohagheghi, Ali; Linger, Jeffrey G.; Yang, Shihui; Smith, Holly; Dowe, Nancy; Zhang, Min; Pienkos, Philip T.

    2015-03-31

    Complete conversion of the major sugars of biomass including both the C5 and C6 sugars is critical for biofuel production processes. Several inhibitory compounds like acetate, hydroxymethylfurfural (HMF), and furfural are produced from the biomass pretreatment process leading to ‘hydrolysate toxicity,’ a major problem for microorganisms to achieve complete sugar utilization. Therefore, development of more robust microorganisms to utilize the sugars released from biomass under toxic environment is critical. In this study, we use continuous culture methodologies to evolve and adapt the ethanologenic bacterium Zymomonas mobilis to improve its ethanol productivity using corn stover hydrolysate. The results are the following:more » A turbidostat was used to adapt the Z. mobilis strain 8b in the pretreated corn stover liquor. The adaptation was initiated using pure sugar (glucose and xylose) followed by feeding neutralized liquor at different dilution rates. Once the turbidostat reached 60% liquor content, the cells began washing out and the adaptation was stopped. Several ‘sub-strains’ were isolated, and one of them, SS3 (sub-strain 3), had 59% higher xylose utilization than the parent strain 8b when evaluated on 55% neutralized PCS (pretreated corn stover) liquor. Using saccharified PCS slurry generated by enzymatic hydrolysis from 25% solids loading, SS3 generated an ethanol yield of 75.5% compared to 64% for parent strain 8b. Furthermore, the total xylose utilization was 57.7% for SS3 versus 27.4% for strain 8b. To determine the underlying genotypes in these new sub-strains, we conducted genomic resequencing and identified numerous single-nucleotide mutations (SNPs) that had arisen in SS3. We further performed quantitative reverse transcription PCR (qRT-PCR) on genes potentially affected by these SNPs and identified significant down-regulation of two genes, ZMO0153 and ZMO0776, in SS3 suggesting potential genetic mechanisms behind SS3’s improved

  10. Analyzing the Effect of Variations in Soil and Management Practices on the Sustainability of Corn Stover-Based Bioethanol Production in Mississippi

    SciTech Connect

    Woli, Prem; Paz, Joel

    2011-08-07

    The inherent variability in corn stover productivity due to variations in soils and crop management practices might contribute to a variation in corn stover-based bioethanol sustainability. This study was carried out to examine how changes in soil types and crop management options would affect corn stover yield (CSY) and the sustainability of the stover-based ethanol production in the Delta region of Mississippi. Based on potential acreage and geographical representation, three locations were selected. Using CERES-Maize model, stover yields were simulated for several scenarios of soils and crop management options. Based on 'net energy value (NEV)' computed from CSYs, a sustainability indicator for stover-based bioethanol production was established. The effects of soils and crop management options on CSY and NEV were determined using ANOVA tests and regression analyses. Both CSY and NEV were significantly different across sandy loam, silt loam, and silty clay loam soils and also across high-, mid-, and low-yielding cultivars. With an increase in irrigation level, both CSY and NEV increased initially and decreased after reaching a peak. A third-degree polynomial relationship was found between planting date and CSY and NEV each. By moving from the lowest to the highest production scenario, values of CSY and NEV could be increased by 86 to 553%, depending on location and weather condition. The effects of variations in soils and crop management options on NEV were the same as on CSY. The NEV was positive for all scenarios, indicating that corn stover-based ethanol production system in the Delta region is sustainable.

  11. Simultaneous saccharification and fermentation of dilute alkaline-pretreated corn stover for enhanced butanol production by Clostridium saccharobutylicum DSM 13864.

    PubMed

    Dong, Jin-Jun; Ding, Ji-Cai; Zhang, Yun; Ma, Li; Xu, Guo-Chao; Han, Rui-Zhi; Ni, Ye

    2016-02-01

    Simultaneous saccharification and fermentation (SSF) process was applied for biobutanol production by Clostridium saccharobutylicum DSM 13864 from corn stover (CS). The key influential factors in SSF process, including corn steep liquor concentration, dry biomass and enzyme loading, SSF temperature, inoculation size and pre-hydrolysis time were optimized. In 5-L bioreactor with SSF process, butanol titer and productivity of 12.3 g/L and 0.257 g/L/h were achieved at 48 h, which were 20.6% and 21.2% higher than those in separate hydrolysis and fermentation (SHF), respectively. The butanol yield reached 0.175 g/g pretreated CS in SSF, representing 50.9% increase than that in SHF (0.116 g/g pretreated CS). This study proves the feasibility of efficient and economic production of biobutanol from CS by SSF. PMID:26764423

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

    SciTech Connect

    Qin, Zhangcai; Canter, Christina E.; Dunn, Jennifer B.; Mueller, Steffen; Kwon, Ho-young; Han, Jeongwoo; Wander, Michelle M.; Wang, Michael

    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

  13. High-titer lactic acid production by Lactobacillus pentosus FL0421 from corn stover using fed-batch simultaneous saccharification and fermentation.

    PubMed

    Hu, Jinlong; Lin, Yanxu; Zhang, Zhenting; Xiang, Ting; Mei, Yuxia; Zhao, Shumiao; Liang, Yunxiang; Peng, Nan

    2016-08-01

    Because the cost of refined sugar substrate and limit of worldwide food availability, lignocellulosic materials are attractive for use in lactic acid (LA) production. In this study, we found Lactobacillus pentosus strain FL0421 produced LA with high yields (0.52-0.82g/g stover) from five NaOH-pretreated and washed agro stovers through simultaneous saccharification and fermentation (SSF). We developed a fed-batch SSF process at 37°C and pH 6.0 using the cellulase of 30FPU/g stover and 10g/L yeast extract in a 5-L bioreactor to produce LA from 14% (w/w) NaOH-pretreated and washed corn stover under non-sterile condition. The LA-titer, yield and productivity reached 92.30g/L, 0.66g/g stover and 1.92g/L/h, respectively; and acetic acid titer and yield reached 34.27g/L and 0.24g/g stover. This study presented a feasible process for LA production from agro stovers and provided a candidate strain for genetic engineering for high-titer and -yield lignocellulosic LA production. PMID:27128191

  14. Enhancement of enzymatic hydrolysis and Klason lignin removal of corn stover using photocatalyst-assisted ammonia pretreatment.

    PubMed

    Yoo, Chang Geun; Wang, Chao; Yu, Chenxu; Kim, Tae Hyun

    2013-03-01

    Photocatalyst-assisted ammonia pretreatment was explored to improve lignin removal of the lignocellulosic biomass for effective sugar conversion. Corn stover was treated with 5.0-12.5 wt.% ammonium hydroxide, two different photocatalysts (TiO(2) and ZnO) in the presence of molecular oxygen in a batch reactor at 60 °C. Various solid-to-liquid ratios (1:20-1:50) were also tested. Ammonia pretreatment assisted by TiO(2)-catalyzed photo-degradation removed 70 % of Klason lignin under the optimum condition (12.5 % ammonium hydroxide, 60 °C, 24 h, solid/liquid=1:20, photocatalyst/biomass=1:10 with oxygen atmosphere). The enzymatic digestibilities of pretreated corn stover were 85 % for glucan and 75 % for xylan with NH(3)-TiO(2)-treated solid and 82 % for glucan and 77 % for xylan with NH(3)-ZnO-treated solid with 15 filter paper units/g-glucan of cellulase and 30 cellobiase units/g-glucan of β-glucosidase, a 2-13 % improvement over ammonia pretreatment alone. PMID:23329141

  15. Natural binders and solid bridge type binding mechanisms in briquettes and pellets made from corn stover and switchgrass.

    PubMed

    Kaliyan, Nalladurai; Morey, R Vance

    2010-02-01

    Corn stover and switchgrass are two important feedstocks considered for producing renewable fuels and energy in the US. Densification of these biomass feedstocks into briquettes/pellets would help reduce the problems and costs of bulk transportation, handling, and storage of biomass feedstocks. In this study, the role of the natural binders in corn stover and switchgrass to make durable particle-particle bonding in briquettes/pellets was investigated by micro-structural analyses. Scanning Electron Microscopy (SEM) images of briquettes made by using a uniaxial piston-cylinder densification apparatus in the laboratory, briquettes made by using a pilot-scale roll-press briquetting machine, and pellets made by using a pilot-scale conventional ring-die pelleting machine were analysed. The SEM images showed that the bonding between particles was created mainly through solid bridges. The solid bridges between particles were made by natural binders in the biomass expressed during the densification process. UV auto-fluorescence images of briquettes and pellets further confirmed that the solid bridges were made mainly by natural binders such as lignin and protein. It was found that activating (softening) the natural binders using moisture and temperature in the range of glass transition is important to make durable particle-particle bonding. PMID:19796933

  16. Acetic acid-catalyzed hydrothermal pretreatment of corn stover for the production of bioethanol at high-solids content.

    PubMed

    Katsimpouras, Constantinos; Christakopoulos, Paul; Topakas, Evangelos

    2016-09-01

    Corn stover (CS) was hydrothermally pretreated using CH3COOH (0.3 %, v/v), and subsequently its ability to be utilized for conversion to ethanol at high-solids content was investigated. Pretreatment conditions were optimized employing a response surface methodology (RSM) with temperature and duration as independent variables. Pretreated CS underwent a liquefaction/saccharification step at a custom designed free-fall mixer at 50 °C for either 12 or 24 h using an enzyme loading of 9 mg/g dry matter (DM) at 24 % (w/w) DM. Simultaneous enzymatic saccharification and fermentation (SSF) of liquefacted corn stover resulted in high ethanol concentration (up to 36.8 g/L), with liquefaction duration having a negligible effect. The threshold of ethanol concentration of 4 % (w/w), which is required to reduce the cost of ethanol distillation, was surpassed by the addition of extra enzymes at the start up of SSF achieving this way ethanol titer of 41.5 g/L. PMID:27145780

  17. A combined sodium phosphate and sodium sulfide pretreatment for enhanced enzymatic digestibility and delignification of corn stover.

    PubMed

    Qing, Qing; Zhou, Linlin; Guo, Qi; Huang, Meizi; He, Yucai; Wang, Liqun; Zhang, Yue

    2016-10-01

    Na3PO4 and Na2S were employed as efficient alkaline catalysts for the pretreatment of corn stover. To systematically obtain optimal conditions, the effects of critical pretreatment parameters including sodium phosphate concentration (1-4%), sulfidity (0-20%), pretreatment temperature (100-120°C), and reaction time (20-60min) on the reducing sugar yield of pretreated substrates were evaluated in a lab-scale using the response surface methodology. Pretreated under the sodium phosphate concentration of 4%, sulfidity of 10%, temperature of 120°C, and reaction time of 40min, the reducing sugar yield and glucose yield of the pretreated corn stover achieved 91.11% and 64.01%, respectively, with a moderate enzyme loading of 30FPU/g substrate. Additionally, a strong correlation (R(2)=0.971 and R(2)=0.954) between the delignification and the reducing sugar yield (or glucose yield) was observed by this pretreatment method. These results evidently support that the combined Na3PO4-Na2S pretreatment is an effective and feasible method for processing lignocellulosic biomass. PMID:27371793

  18. Summary of Findings from the Biomass Refining Consortium for Applied Fundamentals and Innovation (CAFI): Corn Stover Pretreatment

    SciTech Connect

    Elander, R. T.; Dale, B. E.; Holtzapple, M.; Ladisch, M. R.; Lee, Y. Y.; Mitchinson, C.; Saddler, J. N.; Wyman, C. E.

    2009-01-01

    The Biomass Refining Consortium for Applied Fundamentals and Innovation, with members from Auburn University, Dartmouth College, Michigan State University, the National Renewable Energy Laboratory, Purdue University, Texas A&M University, the University of British Columbia, and the University of California at Riverside, has developed comparative data on the conversion of corn stover to sugars by several leading pretreatment technologies. These technologies include ammonia fiber expansion pretreatment, ammonia recycle percolation pretreatment, dilute sulfuric acid pretreatment, flowthrough pretreatment (hot water or dilute acid), lime pretreatment, controlled pH hot water pretreatment, and sulfur dioxide steam explosion pretreatment. Over the course of two separate USDA- and DOE-funded projects, these pretreatment technologies were applied to two different corn stover batches, followed by enzymatic hydrolysis of the remaining solids from each pretreatment technology using identical enzyme preparations, enzyme loadings, and enzymatic hydrolysis assays. Identical analytical methods and a consistent material balance methodology were employed to develop comparative sugar yield data for each pretreatment and subsequent enzymatic hydrolysis. Although there were differences in the profiles of sugar release, with the more acidic pretreatments releasing more xylose directly in the pretreatment step than the alkaline pretreatments, the overall glucose and xylose yields (monomers + oligomers) from combined pretreatment and enzymatic hydrolysis process steps were very similar for all of these leading pretreatment technologies. Some of the water-only and alkaline pretreatment technologies resulted in significant amounts of residual xylose oligomers still remaining after enzymatic hydrolysis that may require specialized enzyme preparations to fully convert xylose oligomers to monomers.

  19. The effects on digestibility and ruminal measures of chemically treated corn stover as a partial replacement for grain in dairy diets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alkaline treatment of gramineous crop residues can convert an abundant, minimally utilized, but poorly digestible straw into a moderately digestible feedstuff. The objective of this study was to evaluate the changes in digestibility and ruminal effects when calcium oxide-treated corn stover was subs...

  20. Technical Aspects of Acceleration of Enzymatic Conversion of Corn Stover Biomass into Bio-fuels by Low Intensity, Uniform Ultrasound Field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the most critical stages of conversion of plant biomass into biofuels employs hydrolysis reactions between highly specific enzymes and matching substrates (e.g. corn stover cellulose with cellulase) that produce soluble sugars, which then could be converted into ethanol. Important benefits of...

  1. Pretreatment of corn stover by low moisture anhydrous ammonia (LMMA) in a pilot-scale reactor and bioconversion to fuel ethanol and industrial chemicals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover (CS) adjusted to 50%, 66% and 70% moisture was pretreated by the low moisture anhydrous ammonia (LMAA) process in a pilot-scale ammoniation reactor. After ammoniation, the 70% moisture CS was treated at 90 degree C and 100 degree C whereas the others were treated at 90 degree C only. The...

  2. Significantly improving enzymatic saccharification of high crystallinity index's corn stover by combining ionic liquid [Bmim]Cl-HCl-water media with dilute NaOH pretreatment.

    PubMed

    He, Yu-Cai; Liu, Feng; Gong, Lei; Zhu, Zheng-Zhong; Ding, Yun; Wang, Cheng; Xue, Yu-Feng; Rui, Huan; Tao, Zhi-Cheng; Zhang, Dan-Ping; Ma, Cui-Luan

    2015-01-01

    In this study, a pretreatment by combining acidified aqueous ionic liquid 1-butyl-3-methylimidazolium chloride (IL [Bmim]Cl) solution with dilute NaOH extraction was employed to pretreat high crystallinity index (CrI) of corn stover before its enzymatic saccharification. After NaOH extraction, [Bmim]Cl-HCl-water (78.8:1.2:20, w/w/w) media was used for further pretreatment at 130 °C for 30 min. After being enzymatically hydrolyzed for 48 h, corn stover pretreated could be biotransformed into reducing sugars in the yield of 95.1%. Furthermore, SEM, XRD and FTIR analyses of untreated and pretreated corn stovers were examined. It was found that the intact structure was disrupted by combination pretreatment and resulted in a porous and amorphous regenerated cellulosic material that greatly improved enzymatic hydrolysis. Finally, the recovered hydrolyzates obtained from the enzymatic hydrolysis of pretreated corn stovers could be fermented into ethanol efficiently. In conclusion, the combination pretreatment shows high potential application in future. PMID:25921785

  3. Fast microwave-assisted catalytic co-pyrolysis of corn stover and scum for bio-oil production with CaO and HZSM-5 as the catalyst.

    PubMed

    Liu, Shiyu; Xie, Qinglong; Zhang, Bo; Cheng, Yanling; Liu, Yuhuan; Chen, Paul; Ruan, Roger

    2016-03-01

    This study investigated fast microwave-assisted catalytic co-pyrolysis of corn stover and scum for bio-oil production with CaO and HZSM-5 as the catalyst. Effects of reaction temperature, CaO/HZSM-5 ratio, and corn stover/scum ratio on co-pyrolysis product fractional yields and selectivity were investigated. Results showed that co-pyrolysis temperature was selected as 550°C, which provides the maximum bio-oil and aromatic yields. Mixed CaO and HZSM-5 catalyst with the weight ratio of 1:4 increased the aromatic yield to 35.77 wt.% of feedstock, which was 17% higher than that with HZSM-5 alone. Scum as the hydrogen donor, had a significant synergistic effect with corn stover to promote the production of bio-oil and aromatic hydrocarbons when the H/C(eff) value exceeded 1. The maximum yield of aromatic hydrocarbons (29.3 wt.%) were obtained when the optimal corn stover to scum ratio was 1:2. PMID:26773959

  4. The effects of chemically treated corn stover as a partial replacement for grain in dairy diets on digestibility and ruminal measures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alkaline treatment of gramineous crop residues can convert an abundant, minimally utilized, but poorly digestible straw into a moderately digestible feedstuff. The objective of this study was to evaluate the changes in digestibility and ruminal effects when calcium oxide-treated corn stover was subs...

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

    PubMed Central

    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

  6. Chemical structures of corn stover and its residue after dilute acid prehydrolysis and enzymatic hydrolysis: Insight into factors limiting enzymatic hydrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Advanced solid-state NMR techniques and wet chemical analyses were applied to investigate untreated corn stover (UCS) and its residues after dilute acid prehydrolysis (DAP) and enzymatic hydrolysis (RES) to provide evidence for the limitations to the effectiveness of enzyme hydrolysis. Advanced soli...

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

    PubMed

    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. PMID:26454367

  8. Impact of AFEX™ Pretreatment and Extrusion Pelleting on Pellet Physical Properties and Sugar Recovery from Corn Stover, Prairie Cord Grass, and Switchgrass.

    PubMed

    Sundaram, Vijay; Muthukumarappan, Kasiviswanathan

    2016-05-01

    The effects of AFEX™ pretreatment, feedstock moisture content (5,10, and 15 % wb), particle size (screen sizes of 2, 4, and 8 mm), and extrusion temperature (75, 100, and 125 °C) on pellet bulk density, pellet hardness, and sugar recovery from corn stover, prairie cord grass, and switchgrass were investigated. Pellets were produced from untreated and AFEX™ pretreated feedstocks using a laboratory-scale extruder. AFEX™ pretreatment increased subsequent pellet bulk density from 453.0 to 650.6 kg m(-3) for corn stover from 463.2 to 680.1 kg m(-3) for prairie cord grass, and from 433.9 to 627.7 kg m(-3) for switchgrass. Maximum pellet hardness of 2342.8, 2424.3, and 1298.6 N was recorded for AFEX™ pretreated corn stover, prairie cord grass, and switchgrass, respectively. Glucose yields of AFEX™ corn stover pellets, prairie cord grass, and switchgrass pellets varied from 88.9 to 94.9 %, 90.1 to 94.9 %, and 87.0 to 92.9 %, respectively. Glucose and xylose yields of AFEX™ pellets were not affected by the extruder barrel temperature and the hammer mill screen size. The results obtained showed that low temperature and large particle size during the extrusion pelleting process can be employed for AFEX™-treated biomass without compromising sugar yields. PMID:26781713

  9. Dilute-sulfuric acid pretreatment of corn stover in pilot-scale reactor: investigation of yields, kinetics, and enzymatic digestibilities of solids.

    PubMed

    Schell, Daniel J; Farmer, Jody; Newman, Millie; McMillan, James D

    2003-01-01

    Corn stover is a domestic feedstock that has potential to produce significant quantities of fuel ethanol and other bioenergy and biobased products. However, comprehensive yield and carbon mass balance information and validated kinetic models for dilute-sulfuric acid (H2SO4) pretreatment of corn stover have not been available. This has hindered the estimation of process economics and also limited the ability to perform technoeconomic modeling to guide research. To better characterize pretreatment and assess its kinetics, we pretreated corn stover in a continuous 1 t/d reactor. Corn stover was pretreated at 20% (w/w) solids concentration over a range of conditions encompassing residence times of 3-12 min, temperatures of 165- 195 degrees C, and H2SO4 concentrations of 0.5-1.4% (w/w). Xylan conversion yield and carbon mass balance data were collected at each run condition. Performance results were used to estimate kinetic model parameters assuming biphasic hemicellulose hydrolysis and a hydrolysis mechanism incorporating formation of intermediate xylo-oligomers. In addition, some of the pretreated solids were tested in a simultaneous saccharification and fermentation (SSF) process to measure the reactivity of their cellulose component to enzymatic digestion by cellulase enzymes. Monomeric xylose yields of 69-71% and total xylose yields (monomers and oligomers) of 70-77% were achieved with performance level depending on pretreatment severity. Cellulose conversion yields in SSF of 80-87% were obtained for some of the most digestible pretreated solids. PMID:12721476

  10. Dilute sulfuric acid pretreatment of corn stover for enzymatic hydrolysis and efficient ethanol production by recombinant Escherichia coli FBR5 without detoxification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A pretreatment strategy for dilute H2SO4 pretreatment of corn stover was developed for the purpose of reducing the generation of inhibitory substances during pretreatment so that a detoxification step is not required prior to fermentation while maximizing the sugar yield. We have optimized dilute su...

  11. Crop and soil responses to using corn stover as a bioenergy feedstock: Observations from the Northern US Corn Belt

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A sustainable bioenergy depends upon soil resources to sustain and increase crop production. This study examined soil (erosion, soil C, and microbial indicators) and crop response to stover removal treatments [Full Residue Returned (FullRR), Moderate Residue Returned (ModRR) and Low Residue Returned...

  12. Co-utilization of corn stover hydrolysates and biodiesel-derived glycerol by Cryptococcus curvatus for lipid production.

    PubMed

    Gong, Zhiwei; Zhou, Wenting; Shen, Hongwei; Zhao, Zongbao K; Yang, Zhonghua; Yan, Jiabao; Zhao, Mi

    2016-11-01

    In the present study, synergistic effects were observed when glycerol was co-fermented with glucose and xylose for lipid production by the oleaginous yeast Cryptococcus curvatus. Glycerol was assimilated simultaneously with sugars at the beginning of the culture without adaption time. Furthermore, better lipid production results, i.e., lipid yield and lipid productivity of 18.0g/100g and 0.13g/L/h, respectively, were achieved when cells were cultured in blends of corn stover hydrolysates and biodiesel-derived glycerol than those in the hydrolysates alone. The lipid samples had fatty acid compositional profiles similar to those of vegetable oils, suggesting their potential for biodiesel production. This co-utilization strategy provides an extremely simple solution to advance lipid production from both lignocelluloses and biodiesel-derived glycerol in one step. PMID:27529520

  13. Recalcitrance and structural analysis by water-only flowthrough pretreatment of 13C enriched corn stover stem

    SciTech Connect

    Foston, Marcus B.; Trajanob, Heather L.; Samuel, Reichel; Wyman, Charles E.; He, Jian; Ragauskas, Arthur J.

    2015-08-28

    Here, this study presents high temperature water-only continuous flowthrough pretreatment coupled with nuclear magnetic resonance (NMR) as a promising analytical tool to examine the plant cell wall, to understand its recalcitrance (i.e., cell wall resistance to deconstruction), and to probe the chemistry occurring during batch pretreatment of biomass. 13C-enriched corn stover stems were pretreated at 170 °C for 60 min with a hot-water flow rate of 20 mL/min to control fractionation of the cell wall. This approach helped elucidate the nature of plant cell wall chemical recalcitrance and biomass pretreatment chemistry by tracking cell wall fragmentation as a function of time. Fractions of the reactor effluent were collected in a time-resolved fashion and characterized by various NMR techniques to determine the degree and sequence of fragments released, as well as, the chemical composition, molecular structure, and relative molecular weight of those released fragments.

  14. Two stage hydrolysis of corn stover at high solids content for mixing power saving and scale-up applications.

    PubMed

    Liu, Ke; Zhang, Jian; Bao, Jie

    2015-11-01

    A two stage hydrolysis of corn stover was designed to solve the difficulties between sufficient mixing at high solids content and high power input encountered in large scale bioreactors. The process starts with the quick liquefaction to convert solid cellulose to liquid slurry with strong mixing in small reactors, then followed the comprehensive hydrolysis to complete saccharification into fermentable sugars in large reactors without agitation apparatus. 60% of the mixing energy consumption was saved by removing the mixing apparatus in large scale vessels. Scale-up ratio was small for the first step hydrolysis reactors because of the reduced reactor volume. For large saccharification reactors in the second step, the scale-up was easy because of no mixing mechanism was involved. This two stage hydrolysis is applicable for either simple hydrolysis or combined fermentation processes. The method provided a practical process option for industrial scale biorefinery processing of lignocellulose biomass. PMID:26253418

  15. Comparison of different mechanical refining technologies on the enzymatic digestibility of low severity acid pretreated corn stover.

    PubMed

    Chen, Xiaowen; Kuhn, Erik; Wang, Wei; Park, Sunkyu; Flanegan, Keith; Trass, Olev; Tenlep, Lisette; Tao, Ling; Tucker, Melvin

    2013-11-01

    The effect of mechanical refining on the enzymatic digestibility of pretreated corn stover (PCS) was investigated. Low severity, dilute sulfuric acid PCS was subjected to mechanical refining using a bench-scale food processor blender, a PFI mill, a 12-inch laboratory disk refiner, and a 25 mm co-rotating twin-screw extruder. Glucose yields from enzymatic hydrolysis were improved by 10-15% after blending and disk refining, while PFI refining and twin-screw extrusion showed a glucose yield improvement of 16-20%. A pilot scale refining test using a Szego mill was performed and showed approximately 10% improvements in biomass digestibility. This suggests the possibility to scale up a mechanical refining technique to obtain similar enzymatic digestibility glucose yield enhancement as achieved by PFI milling and extrusion technologies. Proposed mechanisms of each mechanical refining technology are presented and reasons for improvements in biomass digestibility are discussed in this paper. PMID:24001565

  16. Detoxification of corn stover prehydrolyzate by trialkylamine extraction to improve the ethanol production with Pichia stipitis CBS 5776.

    PubMed

    Zhu, Junjun; Yong, Qiang; Xu, Yong; Yu, Shiyuan

    2011-01-01

    In order to realize the separated ethanol fermentation of glucose and xylose, prehydrolysis of corn stover with sulfuric acid at moderate temperature was applied, while inhibitors were produced inevitably. A complex extraction was adopted to detoxify the prehydrolyzate before fermentation to ethanol with Pichia stipitis CBS 5776. The best proportion of mixed extractant was 30% trialkylamine-50% n-octanol -20% kerosene. Detoxification results indicated that 73.3% of acetic acid, 45.7% of 5-hydroxymethylfurfural and 100% of furfural could be removed. Compared with the undetoxified prehydrolyzate, the fermentability of the detoxified prehydrolyzate was significantly improved. After 48 h fermentation of the detoxified prehydrolyzate containing 7.80 g/l of glucose and 52.8 g/l of xylose, the sugar utilization ratio was 93.2%; the ethanol concentration reached its peak value of 21.8 g/l, which was corresponding to 82.3% of the theoretical value. PMID:20952191

  17. Recalcitrance and structural analysis by water-only flowthrough pretreatment of (13)C enriched corn stover stem.

    PubMed

    Foston, Marcus; Trajano, Heather L; Samuel, Reichel; Wyman, Charles E; He, Jian; Ragauskas, Arthur J

    2015-12-01

    This study presents high temperature water-only continuous flowthrough pretreatment coupled with nuclear magnetic resonance (NMR) as a promising analytical tool to examine the plant cell wall, to understand its recalcitrance (i.e., cell wall resistance to deconstruction), and to probe the chemistry occurring during batch pretreatment of biomass. (13)C-enriched corn stover stems were pretreated at 170°C for 60min with a hot-water flow rate of 20mL/min to control fractionation of the cell wall. This approach helped elucidate the nature of plant cell wall chemical recalcitrance and biomass pretreatment chemistry by tracking cell wall fragmentation as a function of time. Fractions of the reactor effluent were collected in a time-resolved fashion and characterized by various NMR techniques to determine the degree and sequence of fragments released, as well as, the chemical composition, molecular structure, and relative molecular weight of those released fragments. PMID:26320017

  18. Highly efficient production of optically pure l-lactic acid from corn stover hydrolysate by thermophilic Bacillus coagulans.

    PubMed

    Ma, Kedong; Hu, Guoquan; Pan, Liwei; Wang, Zichao; Zhou, Yi; Wang, Yanwei; Ruan, Zhiyong; He, Mingxiong

    2016-11-01

    A thermophilic strain Bacillus coagulans (NBRC 12714) was employed to produce l-lactic acid from corn stover hydrolysate in membrane integrated continuous fermentation. The strain NBRC 12714 metabolized glucose and xylose by the Embden-Meyerhof-Parnas pathway (EMP) and the pentose phosphate pathway (PPP), producing l-lactic acid with optical purity >99.5%. The overall l-lactic acid titer of 92g/l with a yield of 0.91g/g and a productivity of 13.8g/l/h were achieved at a dilution rate of 0.15h(-1). The productivity obtained was 1.6-fold than that of conventional continuous fermentation without cell recycling, and also was the highest among the relevant studies ever reported. These results indicated that the process developed had great potential for economical industrial production of l-lactic acid from lignocellulosic biomass. PMID:27479802

  19. Impact of Sequential Ammonia Fiber Expansion (AFEX) Pretreatment and Pelletization on the Moisture Sorption Properties of Corn Stover

    SciTech Connect

    Bonner, Ian J.; Thompson, David N.; Teymouri, Farzaneh; Campbell, Timothy; Bals, Bryan; Tumuluru, Jaya Shankar

    2015-05-01

    Combining ammonia fiber expansion (AFEX™) pretreatment with a depot processing facility is a promising option for delivering high-value densified biomass to the emerging bioenergy industry. However, because the pretreatment process results in a high moisture material unsuitable for pelleting or storage (40% wet basis), the biomass must be immediately dried. If AFEX pretreatment results in a material that is difficult to dry, the economics of this already costly operation would be at risk. This work tests the nature of moisture sorption isotherms and thin-layer drying behavior of corn (Zea mays L.) stover at 20°C to 60°C before and after sequential AFEX pretreatment and pelletization to determine whether any negative impacts to material drying or storage may result from the AFEX process. The equilibrium moisture content to equilibrium relative humidity relationship for each of the materials was determined using dynamic vapor sorption isotherms and modeled with modified Chung-Pfost, modified Halsey, and modified Henderson temperature-dependent models as well as the Double Log Polynomial (DLP), Peleg, and Guggenheim Anderson de Boer (GAB) temperature-independent models. Drying kinetics were quantified under thin-layer laboratory testing and modeled using the Modified Page's equation. Water activity isotherms for non-pelleted biomass were best modeled with the Peleg temperature-independent equation while isotherms for the pelleted biomass were best modeled with the Double Log Polynomial equation. Thin-layer drying results were accurately modeled with the Modified Page's equation. The results of this work indicate that AFEX pretreatment results in drying properties more favorable than or equal to that of raw corn stover, and pellets of superior physical stability in storage.

  20. Projection of corn production and stover-harvesting impacts on soil organic carbon dynamics in the U.S. Temperate Prairies.

    PubMed

    Wu, Yiping; Liu, Shuguang; Young, Claudia J; Dahal, Devendra; Sohl, Terry L; Davis, Brian

    2015-01-01

    Terrestrial carbon sequestration potential is widely considered as a realistic option for mitigating greenhouse gas emissions. However, this potential may be threatened by global changes including climate, land use, and management changes such as increased corn stover harvesting for rising production of cellulosic biofuel. Therefore, it is critical to investigate the dynamics of soil organic carbon (SOC) at regional or global scale. This study simulated the corn production and spatiotemporal changes of SOC in the U.S. Temperate Prairies, which covers over one-third of the U.S. corn acreage, using a biogeochemical model with multiple climate and land-use change projections. The corn production (either grain yield or stover biomass) could reach 88.7-104.7 TgC as of 2050, 70-101% increase when compared to the base year of 2010. A removal of 50% stover at the regional scale could be a reasonable cap in view of maintaining SOC content and soil fertility especially in the beginning years. The projected SOC dynamics indicated that the average carbon sequestration potential across the entire region may vary from 12.7 to 19.6 g C/m(2)/yr (i.e., 6.6-10.2 g TgC/yr). This study not only helps understand SOC dynamics but also provides decision support for sustainable biofuel development. PMID:26027873

  1. Projection of corn production and stover-harvesting impacts on soil organic carbon dynamics in the U.S. Temperate Prairies

    PubMed Central

    Wu, Yiping; Liu, Shuguang; Young, Claudia J.; Dahal, Devendra; Sohl, Terry L.; Davis, Brian

    2015-01-01

    Terrestrial carbon sequestration potential is widely considered as a realistic option for mitigating greenhouse gas emissions. However, this potential may be threatened by global changes including climate, land use, and management changes such as increased corn stover harvesting for rising production of cellulosic biofuel. Therefore, it is critical to investigate the dynamics of soil organic carbon (SOC) at regional or global scale. This study simulated the corn production and spatiotemporal changes of SOC in the U.S. Temperate Prairies, which covers over one-third of the U.S. corn acreage, using a biogeochemical model with multiple climate and land-use change projections. The corn production (either grain yield or stover biomass) could reach 88.7–104.7 TgC as of 2050, 70–101% increase when compared to the base year of 2010. A removal of 50% stover at the regional scale could be a reasonable cap in view of maintaining SOC content and soil fertility especially in the beginning years. The projected SOC dynamics indicated that the average carbon sequestration potential across the entire region may vary from 12.7 to 19.6 g C/m2/yr (i.e., 6.6–10.2 g TgC/yr). This study not only helps understand SOC dynamics but also provides decision support for sustainable biofuel development. PMID:26027873

  2. Vertical distribution of corn biomass as influenced by cover crop and stover harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) production for grain is important given its many uses for human food, animal feed and other industrial products. Additionally, the abundance and potentially large biomass yield makes corn an attractive bioenergy feedstock. The objective of this study was to evaluate the effect of ...

  3. Corn stover biofuel potential and nutrient removal across the Southeastern US.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) biomass yield and composition vary with variety, plant portion and management practices. It is essential to understand the theoretical ethanol potential of the total and partial corn biomass to determine which parts of the plant should be harvested as biofuel feedstock. Two contin...

  4. Comparative Study of Corn Stover Pretreated by Dilute Acid and Cellulose Solvent-Based Lignocellulose Fractionation: Enzymatic Hydrolysis, Supramolecular Structure, and Substrate Accessibility

    SciTech Connect

    Zhu, Z.; Sathitsuksanoh, N.; Vinzant, T.; Schell, D. J.; McMillian, J. D.; Zhang, Y. H. P.

    2009-07-01

    Liberation of fermentable sugars from recalcitrant biomass is among the most costly steps for emerging cellulosic ethanol production. Here we compared two pretreatment methods (dilute acid, DA, and cellulose solvent and organic solvent lignocellulose fractionation, COSLIF) for corn stover. At a high cellulase loading [15 filter paper units (FPUs) or 12.3 mg cellulase per gram of glucan], glucan digestibilities of the corn stover pretreated by DA and COSLIF were 84% at hour 72 and 97% at hour 24, respectively. At a low cellulase loading (5 FPUs per gram of glucan), digestibility remained as high as 93% at hour 24 for the COSLIF-pretreated corn stover but reached only {approx}60% for the DA-pretreated biomass. Quantitative determinations of total substrate accessibility to cellulase (TSAC), cellulose accessibility to cellulase (CAC), and non-cellulose accessibility to cellulase (NCAC) based on adsorption of a non-hydrolytic recombinant protein TGC were measured for the first time. The COSLIF-pretreated corn stover had a CAC of 11.57 m{sup 2}/g, nearly twice that of the DA-pretreated biomass (5.89 m{sup 2}/g). These results, along with scanning electron microscopy images showing dramatic structural differences between the DA- and COSLIF-pretreated samples, suggest that COSLIF treatment disrupts microfibrillar structures within biomass while DA treatment mainly removes hemicellulose. Under the tested conditions COSLIF treatment breaks down lignocellulose structure more extensively than DA treatment, producing a more enzymatically reactive material with a higher CAC accompanied by faster hydrolysis rates and higher enzymatic digestibility.

  5. Effects of feeding processed corn stover and distillers grains on growth performance and metabolism of beef cattle.

    PubMed

    Chapple, W P; Cecava, M J; Faulkner, D B; Felix, T L

    2015-08-01

    Objectives were to evaluate the effects of replacing corn in feedlot finishing diets with processed corn stover (CS), processed by various combinations of chemical and physical methods, and modified wet distillers grain with solubles (MWDGS) on growth performance, carcass characteristics, digestibility, and ruminal metabolism of cattle. Corn stover was physically processed (ground or extruded) and chemically processed with alkaline agents (CaO and NaOH) to reduce the crystallinity of the lignocellulosic structure. In Exp. 1 steers ( = 18, initial BW = 385 ± 32 kg) and heifers ( = 41, initial BW = 381 ± 27 kg) were allotted to 1 of 5 dietary treatments: 1) 55% dry, cracked corn, 35% MWDGS, 5% vitamin-mineral supplement, and 5% untreated ground CS (), 2) CS treated with 5% CaO (DM basis) and stored in an Ag-Bag (BGCS), 3) CS treated with 5% CaO (DM basis) and extruded (5 EXCS), 4) CS treated with 4% CaO and 1% NaOH (DM basis) and extruded (4,1 EXCS), or 5) CS treated with 3% CaO and 2% NaOH (DM basis) and extruded (3,2 EXCS). Extruded CS was hydrated to 34% moisture, then an additional 16% water was added, as a solution carrying CaO or NaOH or both, via a calibrated pump during processing through a dual-shafted encased extruder (Readco Kurimoto Continuous Processor, York, PA) with the desired exiting temperature of 76.7°C ± 2.8°C. All treated CS diets contained 20% CS and 40% MWDGS (DM basis) to replace 20% corn when compared to CON. There were no effects ( ≥ 0.20) of dietary treatment on ADG, G:F, 12th-rib back fat, marbling score, LM area, or yield grade. However, cattle fed CON had increased ( = 0.02) DMI compared to cattle fed the treated CS diets. In Exp. 2, using the same diets as fed in Exp. 1, ruminally cannulated steers ( = 5; initial BW = 417 ± 21 kg) were fed for 90% of ad libitum intake in a 5 × 5 Latin square design. Apparent digestibility of NDF and ADF increased ( < 0.01) when cattle were fed treated CS diets compared with CON, regardless of

  6. Efficient production of polymer-grade L-lactic acid from corn stover hydrolyzate by thermophilic Bacillus sp. strain XZL4.

    PubMed

    Xue, Zhangwei; Wang, Limin; Ju, Jiansong; Yu, Bo; Xu, Ping; Ma, Yanhe

    2012-01-01

    Lactic acid has been identified as one of the top 30 potential building-block chemicals from biomass. Therefore, the search for cheap raw materials is an objective to reduce the production costs. Efficient polymer-grade L-lactic acid production was achieved in this report by a thermophilic strain Bacillus sp. XZL4 using corn stover hydrolyzate as sole carbon source. High L-lactic acid concentration (81.0 g L(-1)) was obtained from 162.5 g L(-1) concentrated corn stover hydrolyzate (total reducing sugar of 83.0 g L(-1)) with a volumetric productivity of 1.86 g L(-1) h(-1) (0-36 h) and a product yield of 0.98 g g(-1) total reducing sugars. This is the highest L-lactic acid concentration and yield reported from corn stover hydrolyzate. And the high optical purity of L-lactic acid obtained in this study also indicated that Bacillus sp. XZL4 is a promising polymer-grade L-lactic-acid producer from cellulosic biomass. PMID:23961368

  7. Effect of irradiation, as a pretreatment, on bioconversion of corn stover into protein-rich mycelial biomass of Pleurotus sajor-caju

    NASA Astrophysics Data System (ADS)

    Awafo, V. A.; Chahal, D. S.; Charbonneau, R.

    1995-09-01

    Application of irradiation for food preservation, for pretreatment of lignocellulosic materials for their hydrolysis and to increase the digestibility of lignocellulosic materials for rumen animals have been reported in the literature. In the present study, irradiation (100 KGy to 1.7 MGy) of corn stover as a pretreatment to make it susceptible for its bioconversion into protein-rich mycelial biomass of Pleurotus sajor-caju NRRL 18757 has been compared with that of mild alkali treatment (0.01 to 0.15 g NaOH/g corn stover), the most commonly used pretreatment. Protein synthesis increased with the increase in doses of irradiation as well as with the increase in concentration of NaOH. Combination pretreatment with NaOH and γ-irradiation reduced the quantity of NaOH and doses of irradiation required to get optimum yields of protein indicating a strong synergistic effect. The highest protein content of the final product, mycelial biomass, was about 45% on dry weight basis. More than 90% utilization of corn stover polysaccharides for the synthesis of protein-rich mycelial biomass of P. sajor-caju was recorded

  8. Influence of Pyrolysis Temperature on Physico-Chemical Properties of Corn Stover (Zea mays L.) Biochar and Feasibility for Carbon Capture and Energy Balance.

    PubMed

    Rafiq, Muhammad Khalid; Bachmann, Robert Thomas; Rafiq, Muhammad Tariq; Shang, Zhanhuan; Joseph, Stephen; Long, Ruijun

    2016-01-01

    This study examined the influence of pyrolysis temperature on biochar characteristics and evaluated its suitability for carbon capture and energy production. Biochar was produced from corn stover using slow pyrolysis at 300, 400 and 500°C and 2 hrs holding time. The experimental biochars were characterized by elemental analysis, BET, FTIR, TGA/DTA, NMR (C-13). Higher heating value (HHV) of feedstock and biochars was measured using bomb calorimeter. Results show that carbon content of corn stover biochar increased from 45.5% to 64.5%, with increasing pyrolysis temperatures. A decrease in H:C and O:C ratios as well as volatile matter, coupled with increase in the concentration of aromatic carbon in the biochar as determined by FTIR and NMR (C-13) demonstrates a higher biochar carbon stability at 500°C. It was estimated that corn stover pyrolysed at 500°C could provide of 10.12 MJ/kg thermal energy. Pyrolysis is therefore a potential technology with its carbon-negative, energy positive and soil amendment benefits thus creating win- win scenario. PMID:27327870

  9. Influence of Pyrolysis Temperature on Physico-Chemical Properties of Corn Stover (Zea mays L.) Biochar and Feasibility for Carbon Capture and Energy Balance

    PubMed Central

    Rafiq, Muhammad Khalid; Bachmann, Robert Thomas; Rafiq, Muhammad Tariq; Shang, Zhanhuan; Joseph, Stephen; Long, Ruijun

    2016-01-01

    This study examined the influence of pyrolysis temperature on biochar characteristics and evaluated its suitability for carbon capture and energy production. Biochar was produced from corn stover using slow pyrolysis at 300, 400 and 500°C and 2 hrs holding time. The experimental biochars were characterized by elemental analysis, BET, FTIR, TGA/DTA, NMR (C-13). Higher heating value (HHV) of feedstock and biochars was measured using bomb calorimeter. Results show that carbon content of corn stover biochar increased from 45.5% to 64.5%, with increasing pyrolysis temperatures. A decrease in H:C and O:C ratios as well as volatile matter, coupled with increase in the concentration of aromatic carbon in the biochar as determined by FTIR and NMR (C-13) demonstrates a higher biochar carbon stability at 500°C. It was estimated that corn stover pyrolysed at 500°C could provide of 10.12 MJ/kg thermal energy. Pyrolysis is therefore a potential technology with its carbon-negative, energy positive and soil amendment benefits thus creating win- win scenario. PMID:27327870

  10. Coupling alkaline pre-extraction with alkaline-oxidative post-treatment of corn stover to enhance enzymatic hydrolysis and fermentability

    PubMed Central

    2014-01-01

    Background A two-stage chemical pretreatment of corn stover is investigated comprising an NaOH pre-extraction followed by an alkaline hydrogen peroxide (AHP) post-treatment. We propose that conventional one-stage AHP pretreatment can be improved using alkaline pre-extraction, which requires significantly less H2O2 and NaOH. To better understand the potential of this approach, this study investigates several components of this process including alkaline pre-extraction, alkaline and alkaline-oxidative post-treatment, fermentation, and the composition of alkali extracts. Results Mild NaOH pre-extraction of corn stover uses less than 0.1 g NaOH per g corn stover at 80°C. The resulting substrates were highly digestible by cellulolytic enzymes at relatively low enzyme loadings and had a strong susceptibility to drying-induced hydrolysis yield losses. Alkaline pre-extraction was highly selective for lignin removal over xylan removal; xylan removal was relatively minimal (~20%). During alkaline pre-extraction, up to 0.10 g of alkali was consumed per g of corn stover. AHP post-treatment at low oxidant loading (25 mg H2O2 per g pre-extracted biomass) increased glucose hydrolysis yields by 5%, which approached near-theoretical yields. ELISA screening of alkali pre-extraction liquors and the AHP post-treatment liquors demonstrated that xyloglucan and β-glucans likely remained tightly bound in the biomass whereas the majority of the soluble polymeric xylans were glucurono (arabino) xylans and potentially homoxylans. Pectic polysaccharides were depleted in the AHP post-treatment liquor relative to the alkaline pre-extraction liquor. Because the already-low inhibitor content was further decreased in the alkaline pre-extraction, the hydrolysates generated by this two-stage pretreatment were highly fermentable by Saccharomyces cerevisiae strains that were metabolically engineered and evolved for xylose fermentation. Conclusions This work demonstrates that this two

  11. The effects on digestibility and ruminal measures of chemically treated corn stover as a partial replacement for grain in dairy diets.

    PubMed

    Cook, D E; Combs, D K; Doane, P H; Cecava, M J; Hall, M B

    2016-08-01

    Alkaline treatment of gramineous crop residues can convert an abundant, minimally utilized, poorly digestible straw into a moderately digestible feedstuff. Given the volatile nature of grain prices, substitution of treated stover for grain was investigated with dairy cows to provide insights on ruminal and digestibility effects of a feed option that makes use of alternative, available resources. The objective of this study was to evaluate changes in diet digestibility and ruminal effects when increasing levels of calcium oxide-treated corn stover (CaOSt) were substituted for corn grain in diets of lactating cows. Mature corn stover was treated with calcium oxide at a level of 50g∙kg(-1) dry matter (DM), brought up to a moisture content of 50% following bale grinding, and stored anaerobically at ambient temperatures for greater than 60d before the feeding experiment. Eight ruminally cannulated Holstein cows averaging 686kg of body weight and 35kg of milk∙d(-1) were enrolled in a replicated 4×4 Latin square, where CaOSt replaced corn grain on a DM basis in the ration at rates of 0, 40, 80, and 120g∙kg(-1) DM. All reported significant responses were linear. The DM intake declined by approximately 1kg per 4% increase in CaOSt inclusion. With increasing replacement of corn grain, dietary neutral detergent fiber (NDF) concentration increased. However, rumen NDF turnover, NDF digestibility, NDF passage rate, and digestion rate of potentially digestible NDF were unaffected by increasing CaOSt inclusion. Total-tract organic matter digestibility declined by 5 percentage units over the range of treatments, approximately 1.5 units per 4-percentage-unit substitution of CaOSt for grain. With increasing CaOSt, the molar proportions of butyrate and valerate declined, whereas the lowest detected ruminal pH increased from 5.83 to 5.94. Milk, fat, and protein yields declined as CaOSt increased and DM intake declined with the result that net energy in milk declined by

  12. Complex Physiology and Compound Stress Responses during Fermentation of Alkali-Pretreated Corn Stover Hydrolysate by an Escherichia coli Ethanologen

    PubMed Central

    Schwalbach, Michael S.; Tremaine, Mary; Marner, Wesley D.; Zhang, Yaoping; Bothfeld, William; Higbee, Alan; Grass, Jeffrey A.; Cotten, Cameron; Reed, Jennifer L.; da Costa Sousa, Leonardo; Jin, Mingjie; Balan, Venkatesh; Ellinger, James; Dale, Bruce; Kiley, Patricia J.

    2012-01-01

    The physiology of ethanologenic Escherichia coli grown anaerobically in alkali-pretreated plant hydrolysates is complex and not well studied. To gain insight into how E. coli responds to such hydrolysates, we studied an E. coli K-12 ethanologen fermenting a hydrolysate prepared from corn stover pretreated by ammonia fiber expansion. Despite the high sugar content (∼6% glucose, 3% xylose) and relatively low toxicity of this hydrolysate, E. coli ceased growth long before glucose was depleted. Nevertheless, the cells remained metabolically active and continued conversion of glucose to ethanol until all glucose was consumed. Gene expression profiling revealed complex and changing patterns of metabolic physiology and cellular stress responses during an exponential growth phase, a transition phase, and the glycolytically active stationary phase. During the exponential and transition phases, high cell maintenance and stress response costs were mitigated, in part, by free amino acids available in the hydrolysate. However, after the majority of amino acids were depleted, the cells entered stationary phase, and ATP derived from glucose fermentation was consumed entirely by the demands of cell maintenance in the hydrolysate. Comparative gene expression profiling and metabolic modeling of the ethanologen suggested that the high energetic cost of mitigating osmotic, lignotoxin, and ethanol stress collectively limits growth, sugar utilization rates, and ethanol yields in alkali-pretreated lignocellulosic hydrolysates. PMID:22389370

  13. Enhancement of enzymatic saccharification of corn stover with sequential Fenton pretreatment and dilute NaOH extraction.

    PubMed

    He, Yu-Cai; Ding, Yun; Xue, Yu-Feng; Yang, Bin; Liu, Feng; Wang, Cheng; Zhu, Zheng-Zhong; Qing, Qing; Wu, Hao; Zhu, Cheng; Tao, Zhi-Cheng; Zhang, Dan-Ping

    2015-10-01

    In this study, an effective method by the sequential Fenton pretreatment and dilute NaOH extraction (FT-AE) was chosen for pretreating corn stover. Before dilute NaOH (0.75 wt%) extraction at 90 °C for 1h, Fenton reagent (0.95 g/L of FeSO4 and 29.8 g/L of H2O2) was employed to pretreat CS at a solid/liquid ratio of 1/20 (w/w) at 35 °C for 30 min. The changes in the cellulose structural characteristics (porosity, morphology, and crystallinity) of the pretreated solid residue were correlated with the enhancement of enzymatic saccharification. After being enzymatically hydrolyzed for 72 h, the reducing sugars and glucose from the hydrolysis of 60 g/L FT-AE-CS pretreated could be obtained at 40.96 and 23.61 g/L, respectively. Finally, the recovered hydrolyzates containing glucose had no inhibitory effects on the ethanol fermenting microorganism. In conclusion, the sequential Fenton pretreatment and dilute NaOH extraction has high potential application in future. PMID:26142999

  14. Drought effects on composition and yield for corn stover, mixed grasses, and Miscanthus as bioenergy feedstocks

    SciTech Connect

    Emerson, Rachel; Hoover, Amber; Ray, Allison; Lacey, Jeffrey; Cortez, Marnie; Payne, Courtney; Karlen, Douglas; Birrell, Stuart; Laird, David; Kallenbach, Robert; Egenolf, Josh; Sousek, Matthew; Voigt, Thomas

    2014-07-04

    Drought conditions in 2012 were some of the most severe in recent history. The purpose of this study is to examine the impact of drought on quality, quantity, and theoretical ethanol yield (TEY) of three bioenergy feedstocks, corn stover, mixed grasses from Conservation Reserve Program lands, and Miscanthus × giganteus. To assess drought effects on these feedstocks, samples from 2010 (minimal to no drought) and 2012 (severe drought) were compared from multiple locations in the US. In all feedstocks, drought significantly increased extractives and reduced structural sugars and lignin; subsequently, TEYs were reduced 10–15%. Biomass yields were significantly reduced for M. × giganteus and mixed grasses. When reduction in quality and quantity were combined, TEYs decreased 26–59%. Drought negatively affected biomass quality and quantity that resulted in significant TEY reductions. As a result, such fluctuations in biomass quality and yield may have significant consequences for developing lignocellulosic biorefineries.

  15. Reactor performance and microbial community dynamics during solid-state anaerobic digestion of corn stover at mesophilic and thermophilic conditions.

    PubMed

    Shi, Jian; Wang, Zhongjiang; Stiverson, Jill A; Yu, Zhongtang; Li, Yebo

    2013-05-01

    Reactor performance and microbial community dynamics were investigated during solid state anaerobic digestion (SS-AD) of corn stover at mesophilic and thermophilic conditions. Thermophilic SS-AD led to faster and greater reductions of cellulose and hemicelluloses during the first 12 days compared to mesophilic SS-AD. However, accumulation of volatile fatty acids (VFAs) was 5-fold higher at thermophilic than mesophilic temperatures, resulting in a large pH drop during days 6-12 in the thermophilic reactors. Culture-based enumeration revealed 10-50 times greater populations of cellulolytic and xylanolytic microbes during thermophilic SS-AD than mesophilic SS-AD. DGGE analysis of PCR amplified 16S rRNA genes showed dynamic shifts, especially during the thermophilic SS-AD, of bacterial and archaeal communities over the 38 days of SS-AD as a result of acclimation of the initial seed microbial consortia to the lignocellulosic feedstock. The findings of this study can guide future studies to improve efficiency and stability of SS-AD. PMID:23567733

  16. Enzymatic liquefaction and saccharification of pretreated corn stover at high-solids concentrations in a horizontal rotating bioreactor.

    PubMed

    Du, Jian; Zhang, Fazhan; Li, Yuanyuan; Zhang, Hongman; Liang, Jingrui; Zheng, Hongbo; Huang, He

    2014-02-01

    A self-designed horizontal rotating bioreactor (HRR) was applied for enzymatic hydrolysis of pretreated corn stover to improve the process economics of ethanol production. The mixing principle was based on gravity and free fall employed with tank-rotating. The liquefaction performances using the HRR and the vertical stirred-tank reactor (VSTR) with a helical impeller were compared and analyzed by measuring rheological properties of the slurry. During the enzymatic hydrolysis, viscosity decreased dramatically in the initial phase for both bioreactors and more pronouncedly for the HRR. Rheological parameters fitted to the power law showed that shear thinning properties of the slurry weakened during the reaction. The glucose concentration was used to define the efficiency of the saccharification reaction. The HRR also proved to be more efficient for glucose release with both the constant and fed-batch substrate addition modes. Liquefaction and saccharification at 25% w/w dry matter (DM) and enzyme loading of 7 FPU/g DM resulted in the optimal glucose concentration of 86 g/kg. Results revealed a decrease in cellulose conversion at increasing initial DM, which was slighter in the HRR compared with that in the VSTR. PMID:23771162

  17. Recalcitrance and structural analysis by water-only flowthrough pretreatment of 13C enriched corn stover stem

    DOE PAGESBeta

    Foston, Marcus B.; Trajanob, Heather L.; Samuel, Reichel; Wyman, Charles E.; He, Jian; Ragauskas, Arthur J.

    2015-08-28

    Here, this study presents high temperature water-only continuous flowthrough pretreatment coupled with nuclear magnetic resonance (NMR) as a promising analytical tool to examine the plant cell wall, to understand its recalcitrance (i.e., cell wall resistance to deconstruction), and to probe the chemistry occurring during batch pretreatment of biomass. 13C-enriched corn stover stems were pretreated at 170 °C for 60 min with a hot-water flow rate of 20 mL/min to control fractionation of the cell wall. This approach helped elucidate the nature of plant cell wall chemical recalcitrance and biomass pretreatment chemistry by tracking cell wall fragmentation as a function ofmore » time. Fractions of the reactor effluent were collected in a time-resolved fashion and characterized by various NMR techniques to determine the degree and sequence of fragments released, as well as, the chemical composition, molecular structure, and relative molecular weight of those released fragments.« less

  18. Effect of Lignin Removal by Alkaline Peroxide Pretreatment on the Susceptibility of Corn Stover to Purified Cellulolytic and Xylanolytic Enzymes

    SciTech Connect

    Selig, M. J.; Vinzant, T. B.; Himmel, M. E.; Decker, S. R.

    2009-01-01

    Pretreatment of corn stover with alkaline peroxide (AP) at pH 11.5 resulted in reduction of lignin content in the residual solids as a function of increasing batch temperature. Scanning electron microscopy of these materials revealed notably more textured surfaces on the plant cell walls as a result of the delignifying pretreatment. As expected, digestion of the delignified samples with commercial cellulase preparations showed an inverse relationship between the content of lignin present in the residual solids after pretreatment and the extent of both glucan and xylan conversion achievable. Digestions with purified enzymes revealed that decreased lignin content in the pretreated solids did not significantly impact the extent of glucan conversion achievable by cellulases alone. Not until purified xylanolytic activities were included with the cellulases were significant improvements in glucan conversion realized. In addition, an inverse relationship was observed between lignin content after pretreatment and the extent of xylan conversion achievable in a 24-h period with the xylanolytic enzymes in the absence of the cellulases. This observation, coupled with the direct relationship between enzymatic xylan and glucan conversion observed in a number of cases, suggests that the presence of lignins may not directly occlude cellulose present in lignocelluloses but rather impact cellulase action indirectly by its association with xylan.

  19. Life cycle assessment of the production of hydrogen and transportation fuels from corn stover via fast pyrolysis

    NASA Astrophysics Data System (ADS)

    Zhang, Yanan; Hu, Guiping; Brown, Robert C.

    2013-06-01

    This life cycle assessment evaluates and quantifies the environmental impacts of the production of hydrogen and transportation fuels from the fast pyrolysis and upgrading of corn stover. Input data for this analysis come from Aspen Plus modeling, a GREET (Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation) model database and a US Life Cycle Inventory Database. SimaPro 7.3 software is employed to estimate the environmental impacts. The results indicate that the net fossil energy input is 0.25 MJ and 0.23 MJ per km traveled for a light-duty vehicle fueled by gasoline and diesel fuel, respectively. Bio-oil production requires the largest fossil energy input. The net global warming potential (GWP) is 0.037 kg CO2eq and 0.015 kg CO2eq per km traveled for a vehicle fueled by gasoline and diesel fuel, respectively. Vehicle operations contribute up to 33% of the total positive GWP, which is the largest greenhouse gas footprint of all the unit processes. The net GWPs in this study are 88% and 94% lower than for petroleum-based gasoline and diesel fuel (2005 baseline), respectively. Biomass transportation has the largest impact on ozone depletion among all of the unit processes. Sensitivity analysis shows that fuel economy, transportation fuel yield, bio-oil yield, and electricity consumption are the key factors that influence greenhouse gas emissions.

  20. Simultaneous saccharification and co-fermentation for improving the xylose utilization of steam exploded corn stover at high solid loading.

    PubMed

    Liu, Zhi-Hua; Chen, Hong-Zhang

    2016-02-01

    Simultaneous saccharification and co-fermentation (SSCF) of steam exploded corn stover (SECS) was investigated at 5-25% solid loadings compared with other conversion processes. SECS was washed with a 15-fold excess of deionized water to remove inhibitors of hydrolysis and fermentation. The concentration, yield, and productivity of ethanol was 34.3g/L, 90.0%, 2.61g/L/h in the co-fermentation of 60g/L glucose and 10g/L xylose by Saccharomyces cerevisiae IPE003. Ethanol concentration and productivity increased with increasing solid loading while ethanol yield decreased in all conversion processes of SECS. Glucan and xylan conversion was 82.0% and 82.1% in SSCF at 20% solid loading, respectively, while the concentration, yield and productivity of ethanol was 60.8g/L, 75.3% and 0.63g/L/h. The feeding strategy of SECS addition within 24h improved the SSCF performance. Therefore, SSCF increased ethanol productivity and was an effective conversion process for ethanol production at high solid loading. PMID:26615497

  1. Integrated chemical and multi-scale structural analyses for the processes of acid pretreatment and enzymatic hydrolysis of corn stover.

    PubMed

    Chen, Longjian; Li, Junbao; Lu, Minsheng; Guo, Xiaomiao; Zhang, Haiyan; Han, Lujia

    2016-05-01

    Corn stover was pretreated with acid under moderate conditions (1.5%, w/w, 121°C, 60min), and kinetic enzymolysis experiments were performed on the pretreated substrate using a mixture of Celluclast 1.5L (20FPU/g dry substrate) and Novozyme 188 (40CBU/g dry substrate). Integrated chemical and multi-scale structural methods were then used to characterize both processes. Chemical analysis showed that acid pretreatment removed considerable hemicellulose (from 19.7% in native substrate to 9.28% in acid-pretreated substrate) and achieved a reasonably high conversion efficiency (58.63% of glucose yield) in the subsequent enzymatic hydrolysis. Multi-scale structural analysis indicated that acid pretreatment caused structural changes via cleaving acetyl linkages, solubilizing hemicellulose, relocating cell wall surfaces and enlarging substrate porosity (pore volume increased from 0.0067cm(3)/g in native substrate to 0.019cm(3)/g in acid-pretreated substrate), thereby improving the polysaccharide digestibility. PMID:26876990

  2. Non-severe thermochemical hydrolysis of stover from white corn and sequential enzymatic saccharification and fermentation to ethanol.

    PubMed

    Vargas-Tah, Alejandra; Moss-Acosta, Cessna L; Trujillo-Martinez, Berenice; Tiessen, Axel; Lozoya-Gloria, Edmundo; Orencio-Trejo, Montserrat; Gosset, Guillermo; Martinez, Alfredo

    2015-12-01

    A parametric study, with an initial load of 15%w/w of dry stover from white corn, was conducted to evaluate the sequential thermochemical hydrolysis (TH), enzymatic saccharification (ES) and fermentation of the whole slurry with ethanologenic Escherichia coli. The TH was designed to release the maximum amount of xylose with a concomitant formation of minimal amounts of furans. It was found that 29.0% or 93.2% of the xylan was recovered as free xylose at 130°C after 8 min in the presence of 1% or 2%w/w H2SO4 and produced only 0.06 or 0.44 g/L of total furans, respectively. After 24h of ES, 76.14-77.18 g/L of monosaccharides (pentoses and hexoses) were obtained. These slurries, which contained 0.03-0.26 g/L of total furans and 5.14-5.91 g/L of acetate, were fermented with 3.7 g/L of ethanologenic E. coli to produce 24.5-23.5 g/L of ethanol. PMID:26433785

  3. Enhancing methane production of corn stover through a novel way: sequent pretreatment of potassium hydroxide and steam explosion.

    PubMed

    Li, Jianghao; Zhang, Ruihong; Siddhu, Muhammad Abdul Hanan; He, Yanfeng; Wang, Wen; Li, Yeqing; Chen, Chang; Liu, Guangqing

    2015-04-01

    Getting over recalcitrance of lignocellulose is effective way to fuel production from lignocellulosic biomass. In current work, different pretreatments were applied to enhance the digestibility of corn stover (CS). Results showed that steam explosion (SE)-treated CS produced maximal methane yield (223.2 mL/gvs) at 1.2 MPa for 10 min, which was 55.2% more than untreated (143.8 mL/gvs). Whereas 1.5% KOH-treated CS produced maximum methane yield of 208.6 mL/gvs, and significantly (α<0.05) improved 45.1% with respect to untreated. Sequent pretreatment of potassium hydroxide and steam explosion (SPPE) (1.5% KOH-1.2 MPa, 10 min) achieved a very significant (α<0.01) improvement (80.0%) of methane yield (258.8 mL/gvs) compared with untreated CS. Methane production could be well explained by the first-order and modified Gompertz models. Besides, SEM, FTIR, and XRD analyses validated structural changes of CS after SPPE. SPPE might be a promising method to pretreat CS in the future AD industry. PMID:25681690

  4. Genetic engineering and improvement of a Zymomonas mobilis for arabinose utilization and its performance on pretreated corn stover hydrolyzate

    DOE PAGESBeta

    Chou, Yat -Chen; Linger, Jeffrey; Yang, Shihui; Zhang, Min

    2015-04-28

    In this paper, a glucose, xylose and arabinose utilizing Zymomonas mobilis strain was constructed by incorporating arabinose catabolic pathway genes, araBAD encoding L-ribulokinase, L-arabinose isomerase and L-ribulose-5-phosphate- 4-epimerase in a glucose, xylose co-fermenting host, 8b, using a transposition integration approach. Further improvement on this arabinose-capable integrant, 33C was achieved by applying a second transposition to create a genomic knockout (KO) mutant library. Using arabinose as a sole carbon source and a selection pressure, the KO library was subjected to a growth-enrichment process involving continuous sub-culturing for over 120 generations. Strain 13-1-17, isolated from such process demonstrated significant improvement in metabolizingmore » arabinose in a dilute acid pretreated, saccharified corn stover slurry. Through Next Generation Sequencing (NGS) analysis, integration sites of the transposons were identified. Furthermore, multiple additional point mutations (SNPs: Single Nucleotide Polymorphisms) were discovered in 13-1-17, affecting genes araB and RpiB in the genome. Finally, we speculate that these mutations may have impacted the expression of the enzymes coded by these genes, ribulokinase and Ribose 5-P-isomerase, thus attributing to the improvement of the arabinose utilization.« less

  5. Identification of oleaginous yeast strains able to accumulate high intracellular lipids when cultivated in alkaline pretreated corn stover

    PubMed Central

    Sitepu, Irnayuli R.; Jin, Mingjie; Fernandez, J. Enrique; da Costa Sousa, Leonardo; Balan, Venkatesh; Boundy-Mills, Kyria L.

    2015-01-01

    Microbial oil is a potential alternative to food/plant-derived biodiesel fuel. Our previous screening studies identified a wide range of oleaginous yeast species, using a defined laboratory medium known to stimulate lipid accumulation. In this study, the ability of these yeasts to grow and accumulate lipids was further investigated in synthetic hydrolysate (SynH) and authentic ammonia fiber expansion (AFEX™)-pretreated corn stover hydrolysate (ACSH). Most yeast strains tested were able to accumulate lipids in SynH, but only a few were able to grow and accumulate lipids in ACSH medium. Cryptococcus humicola UCDFST 10-1004 was able to accumulate as high as 15.5 g/L lipids, out of a total of 36 g/L cellular biomass when grown in ACSH, with a cellular lipid content of 40% of cell dry weight. This lipid production is among the highest reported values for oleaginous yeasts grown in authentic hydrolysate. Pre-culturing in SynH media with xylose as sole carbon source enabled yeasts to assimilate both glucose and xylose more efficiently in the subsequent hydrolysate medium. This study demonstrates that ACSH is a suitable medium for certain oleaginous yeasts to convert lignocellullosic sugars to triacylglycerols for production of biodiesel and other valuable oleochemicals. PMID:25052467

  6. ENGINEERING, NUTRIENT REMOVAL, AND FEEDSTOCK CONVERSION EVALUATIONS OF FOUR CORN STOVER HARVEST SCENARIOS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop residue has been identified as a near-term source of biomass for renewable fuel, heat, power, chemicals and other bio-materials. A prototype one-pass harvest system was used to collect residue samples from a corn (Zea mays L.) field near Ames, IA. Four harvest scenarios (low cut, high-cut top, ...

  7. Method to Produce Durable Pellets at Lower Energy Consumption Using High Moisture Corn Stover and a Corn Starch Binder in a Flat Die Pellet Mill.

    PubMed

    Tumuluru, Jaya Shankar; Conner, Craig C; Hoover, Amber N

    2016-01-01

    A major challenge in the production of pellets is the high cost associated with drying biomass from 30 to 10% (w.b.) moisture content. At Idaho National Laboratory, a high-moisture pelleting process was developed to reduce the drying cost. In this process the biomass pellets are produced at higher feedstock moisture contents than conventional methods, and the high moisture pellets produced are further dried in energy efficient dryers. This process helps to reduce the feedstock moisture content by about 5-10% during pelleting, which is mainly due to frictional heat developed in the die. The objective of this research was to explore how binder addition influences the pellet quality and energy consumption of the high-moisture pelleting process in a flat die pellet mill. In the present study, raw corn stover was pelleted at moistures of 33, 36, and 39% (w.b.) by addition of 0, 2, and 4% pure corn starch. The partially dried pellets produced were further dried in a laboratory oven at 70 °C for 3-4 hr to lower the pellet moisture to less than 9% (w.b.). The high moisture and dried pellets were evaluated for their physical properties, such as bulk density and durability. The results indicated that increasing the binder percentage to 4% improved pellet durability and reduced the specific energy consumption by 20-40% compared to pellets with no binder. At higher binder addition (4%), the reduction in feedstock moisture during pelleting was <4%, whereas the reduction was about 7-8% without the binder. With 4% binder and 33% (w.b.) feedstock moisture content, the bulk density and durability values observed of the dried pellets were >510 kg/m(3) and >98%, respectively, and the percent fine particles generated was reduced to <3%. PMID:27340875

  8. Method to Produce Durable Pellets at Lower Energy Consumption Using High Moisture Corn Stover and a Corn Starch Binder in a Flat Die Pellet Mill

    PubMed Central

    Tumuluru, Jaya Shankar; Conner, Craig C.; Hoover, Amber N.

    2016-01-01

    A major challenge in the production of pellets is the high cost associated with drying biomass from 30 to 10% (w.b.) moisture content. At Idaho National Laboratory, a high-moisture pelleting process was developed to reduce the drying cost. In this process the biomass pellets are produced at higher feedstock moisture contents than conventional methods, and the high moisture pellets produced are further dried in energy efficient dryers. This process helps to reduce the feedstock moisture content by about 5-10% during pelleting, which is mainly due to frictional heat developed in the die. The objective of this research was to explore how binder addition influences the pellet quality and energy consumption of the high-moisture pelleting process in a flat die pellet mill. In the present study, raw corn stover was pelleted at moistures of 33, 36, and 39% (w.b.) by addition of 0, 2, and 4% pure corn starch. The partially dried pellets produced were further dried in a laboratory oven at 70 °C for 3-4 hr to lower the pellet moisture to less than 9% (w.b.). The high moisture and dried pellets were evaluated for their physical properties, such as bulk density and durability. The results indicated that increasing the binder percentage to 4% improved pellet durability and reduced the specific energy consumption by 20-40% compared to pellets with no binder. At higher binder addition (4%), the reduction in feedstock moisture during pelleting was <4%, whereas the reduction was about 7-8% without the binder. With 4% binder and 33% (w.b.) feedstock moisture content, the bulk density and durability values observed of the dried pellets were >510 kg/m3 and >98%, respectively, and the percent fine particles generated was reduced to <3%. PMID:27340875

  9. Direct mechanical energy measures of hammer mill comminution of switchgrass, wheat straw, and corn stover and analysis of their particle size distributions

    SciTech Connect

    Bitra, V.S.P; Womac, A.R.; Chevanan, Nehru; Miu, P.I.; Smith, D.R.; Igathinathane, C.; Sokhansanj, Shahabaddine

    2009-07-01

    Biomass particle size impacts handling, storage, conversion, and dust control systems. Size reduction mechanical energy was directly measured for switchgrass (Panicum virgatum L.), wheat straw (Triticum aestivum L.), and corn stover (Zea mays L.) in an instrumented hammer mill. Direct energy inputs were determined for hammer mill operating speeds from 2000 to 3600 rpm for 3.2 mm integral classifying screen and mass input rate of 2.5 kg/min with 90 - and 30 -hammers. Overall accuracy of specific energy measurement was calculated as 0.072 MJ/Mg. Particle size distributions created by hammer mill were determined for mill operating factors using ISO sieve sizes from 4.75 to 0.02 mm in conjunction with Ro-Tap sieve analyzer. A wide range of analytical descriptors were examined to mathematically represent the range of particle sizes in the distributions. Total specific energy (MJ/Mg) was defined as size reduction energy to operate the hammer mill plus that imparted to biomass. Effective specific energy was defined as energy imparted to biomass. Total specific energy for switchgrass, wheat straw, and corn stover grinding increased by 37, 30, and 45% from 114.4, 125.1, and 103.7 MJ/Mg, respectively, with an increase in hammer mill speed from 2000 to 3600 rpm for 90 -hammers. Corresponding total specific energy per unit size reduction was 14.9, 19.7, and 13.5 MJ/Mg mm, respectively. Effective specific energy of 90 -hammers decreased marginally for switchgrass and considerably for wheat straw and it increased for corn stover with an increase in speed from 2000 to 3600 rpm. However, effective specific energy increased with speed to a certain extent and then decreased for 30 -hammers. Rosin Rammler equation fitted the size distribution data with R2 > 0.995. Mass relative span was greater than 1, which indicated a wide distribution of particle sizes. Hammer milling of switchgrass, wheat straw, and corn stover with 3.2 mm screen resulted in well-graded fine-skewed mesokurtic

  10. Tween 40 pretreatment of unwashed water-insoluble solids of reed straw and corn stover pretreated with liquid hot water to obtain high concentrations of bioethanol

    PubMed Central

    2013-01-01

    Background Liquid hot water (LHW) pretreatment is an effective and environmentally friendly method to produce bioethanol with lignocellulosic materials. In our previous study, high ethanol concentration and ethanol yield were obtained from water-insoluble solids (WIS) of reed straw and corn stover pretreated with LHW by using fed-batch semi-simultaneous saccharification and fermentation (S-SSF). However, high cellulase loading and the large amount of wash water possibly limit the practical application of LHW pretreatment. To decrease cellulase loading and the amount of wash water, we performed Tween 40 pretreatment before WIS was subjected to bioethanol fermentation. Results Results showed that the optimum conditions of Tween 40 pretreatment were as follows: Tween 40 concentration of 1.5%, WIS-to-Tween 40 ratio of 1:10 (w/v), and pretreatment time of 1 hour at ambient temperature. After Tween 40 pretreatment, cellulase loading could be greatly reduced. After Tween 40 pretreatment, the residual liquid could be recycled for utilization but slightly affected ethanol concentration and yield. The unwashed WIS could obtain a high ethanol concentration of 56.28 g/L (reed straw) and 52.26 g/L (corn stover) by Tween 40 pretreatment using fed-batch S-SSF. Ethanol yield reached a maximum of 69.1% (reed straw) and 71.1% (corn stover). Conclusions Tween 40 pretreatment was a very effective and less costly method with unwashed WIS. This pretreatment could greatly reduce cellulase loading and save wash water. Higher ethanol concentration was obtained almost without reducing ethanol yield. PMID:24206614

  11. Catalyst Transport in Corn Stover Internodes: Elucidating Transport Mechanisms Using Direct Blue-I

    SciTech Connect

    Viamajala, S.; Selig, M. J.; Vinzant, T. B.; Tucker, M. P.; Himmel, M. E.; McMillan, J. D.; Decker, S. R.

    2006-04-01

    The transport of catalysts (chemicals and enzymes) within plant biomass is believed to be a major bottleneck during thermochemical pretreatment and enzymatic conversion of lignocellulose. Subjecting biomass to size reduction and mechanical homogenization can reduce catalyst transport limitations; however, such processing adds complexity and cost to the over-all process. Using high-resolution light microscopy, we have monitored the transport of an aqueous solution of Direct Blue-I (DB-I) dye through intact corn internodes under a variety of impregnation conditions. DB-I is a hydrophilic anionic dye with affinity for cellulose. This model system has enabled us to visualize likely barriers and mechanisms of catalyst transport in corn stems. Microscopic images were compared with calculated degrees of saturation (i.e., volume fraction of internode void space occupied by dye solution) to correlate impregnation strategies with dye distribution and transport mechanisms. Results show the waxy rind exterior and air trapped within individual cells to be the major barriers to dye transport, whereas the vascular bundles, apoplastic continuum (i.e., the intercellular void space at cell junctions), and fissures formed during the drying process provided the most utilized pathways for transport. Although representing only 20-30% of the internode volume, complete saturation of the apoplast and vascular bundles by fluid allowed dye contact with a majority of the cells in the internode interior.

  12. Bed Agglomeration During the Steam Gasification of a High Lignin Corn Stover Simultaneous Saccharification and Fermentation (SSF) Digester Residue

    SciTech Connect

    Howe, Daniel T.; Taasevigen, Danny J.; Gerber, Mark A.; Gray, Michel J.; Fernandez, Carlos A.; Saraf, Laxmikant; Garcia-Perez, Manuel; Wolcott, Michael P.

    2015-11-13

    This research investigates the bed agglomeration phenomena during the steam gasification of a high lignin residue produced from the simultaneous saccharification and fermentation (SSF) of corn stover in a bubbling fluidized bed. The studies were conducted at 895°C using alumina as bed material. Biomass was fed at 1.5 kg/hr, while steam was fed to give a velocity equal to 2.5 times the minimum fluidization velocity, with a steam/carbon ratio of 0.9. The pelletized feedstock was co-fed with a cooling nitrogen stream to mitigate feed line plugging issues. Tar production was high at 50.3 g/Nm3, and the fraction of C10+ compounds was greater than that seen in the gasification of traditional lignocellulosic feedstocks. Carbon closures over 94 % were achieved for all experiments. Bed agglomeration was found to be problematic, indicated by pressure drop increases observed below the bed and upstream of the feed line. Two size categories of solids were recovered from the reactor, +60 mesh and -60 mesh. After a 2.75-hour experiment, 61.7 wt % was recovered as -60 mesh particles and 38.2 wt% of the recovered reactor solids were +60 mesh. A sizeable percentage, 31.8 wt%, was +20 mesh. The -60 mesh particles were mainly formed by the initial bed material (Al2O3). Almost 50 wt. % of the + 20 mesh particles was found to be formed by organics. The unreacted carbon remaining in the reactor resulted in a low conversion rate to product gas. ICP-AES, SEM, SEM-EDS, and XRD confirmed that the large agglomerates (+ 20 mesh) were not encapsulated bed material but rather un-gasified feedstock pellets with sand particles attached to it.

  13. Effect of process variables on the density and durability of the pellets made from high moisture corn stover

    SciTech Connect

    Jaya Shankar Tumuluru

    2014-03-01

    A flat die pellet mill was used to understand the effect of high levels of feedstock moisture content in the range of 28–38% (w.b.), with die rotational speeds of 40–60 Hz, and preheating temperatures of 30–110 °C on the pelleting characteristics of 4.8 mm screen size ground corn stover using an 8 mm pellet die. The physical properties of the pelletised biomass studied are: (a) pellet moisture content, (b) unit, bulk and tapped density, and (c) durability. Pelletisation experiments were conducted based on central composite design. Analysis of variance (ANOVA) indicated that feedstock moisture content influenced all of the physical properties at P < 0.001. Pellet moisture content decreased with increase in preheating temperature to about 110 °C and decreasing the feedstock moisture content to about 28% (w.b.). Response surface models developed for quality attributes with respect to process variables has adequately described the process with coefficient of determination (R2) values of >0.88. The other pellet quality attributes such as unit, bulk, tapped density, were maximised at feedstock moisture content of 30–33% (w.b.), die speeds of >50 Hz and preheating temperature of >90 °C. In case of durability a medium moisture content of 33–34% (w.b.) and preheating temperatures of >70 °C and higher die speeds >50 Hz resulted in high durable pellets. It can be concluded from the present study that feedstock moisture content, followed by preheating, and die rotational speed are the interacting process variables influencing pellet moisture content, unit, bulk and tapped density and durability.

  14. Acetic acid removal from corn stover hydrolysate using ethyl acetate and the impact on Saccharomyces cerevisiae bioethanol fermentation.

    PubMed

    Aghazadeh, Mahdieh; Ladisch, Michael R; Engelberth, Abigail S

    2016-07-01

    Acetic acid is introduced into cellulose conversion processes as a consequence of composition of lignocellulose feedstocks, causing significant inhibition of adapted, genetically modified and wild-type S. cerevisiae in bioethanol fermentation. While adaptation or modification of yeast may reduce inhibition, the most effective approach is to remove the acetic acid prior to fermentation. This work addresses liquid-liquid extraction of acetic acid from biomass hydrolysate through a pathway that mitigates acetic acid inhibition while avoiding the negative effects of the extractant, which itself may exhibit inhibition. Candidate solvents were selected using simulation results from Aspen Plus™, based on their ability to extract acetic acid which was confirmed by experimentation. All solvents showed varying degrees of toxicity toward yeast, but the relative volatility of ethyl acetate enabled its use as simple vacuum evaporation could reduce small concentrations of aqueous ethyl acetate to minimally inhibitory levels. The toxicity threshold of ethyl acetate, in the presence of acetic acid, was found to be 10 g L(-1) . The fermentation was enhanced by extracting 90% of the acetic acid using ethyl acetate, followed by vacuum evaporation to remove 88% removal of residual ethyl acetate along with 10% of the broth. NRRL Y-1546 yeast was used to demonstrate a 13% increase in concentration, 14% in ethanol specific production rate, and 11% ethanol yield. This study demonstrated that extraction of acetic acid with ethyl acetate followed by evaporative removal of ethyl acetate from the raffinate phase has potential to significantly enhance ethanol fermentation in a corn stover bioethanol facility. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:929-937, 2016. PMID:27090191

  15. Improving a recombinant Zymomonas mobilis strain 8b through continuous adaptation on dilute acid pretreated corn stover hydrolysate

    SciTech Connect

    Mohagheghi, Ali; Linger, Jeffrey G.; Yang, Shihui; Smith, Holly; Dowe, Nancy; Zhang, Min; Pienkos, Philip T.

    2015-03-31

    Complete conversion of the major sugars of biomass including both the C5 and C6 sugars is critical for biofuel production processes. Several inhibitory compounds like acetate, hydroxymethylfurfural (HMF), and furfural are produced from the biomass pretreatment process leading to ‘hydrolysate toxicity,’ a major problem for microorganisms to achieve complete sugar utilization. Therefore, development of more robust microorganisms to utilize the sugars released from biomass under toxic environment is critical. In this study, we use continuous culture methodologies to evolve and adapt the ethanologenic bacterium Zymomonas mobilis to improve its ethanol productivity using corn stover hydrolysate. The results are the following: A turbidostat was used to adapt the Z. mobilis strain 8b in the pretreated corn stover liquor. The adaptation was initiated using pure sugar (glucose and xylose) followed by feeding neutralized liquor at different dilution rates. Once the turbidostat reached 60% liquor content, the cells began washing out and the adaptation was stopped. Several ‘sub-strains’ were isolated, and one of them, SS3 (sub-strain 3), had 59% higher xylose utilization than the parent strain 8b when evaluated on 55% neutralized PCS (pretreated corn stover) liquor. Using saccharified PCS slurry generated by enzymatic hydrolysis from 25% solids loading, SS3 generated an ethanol yield of 75.5% compared to 64% for parent strain 8b. Furthermore, the total xylose utilization was 57.7% for SS3 versus 27.4% for strain 8b. To determine the underlying genotypes in these new sub-strains, we conducted genomic resequencing and identified numerous single-nucleotide mutations (SNPs) that had arisen in SS3. We further performed quantitative reverse transcription PCR (qRT-PCR) on genes potentially affected by these SNPs and identified significant down-regulation of two genes, ZMO0153 and ZMO0776, in SS3 suggesting potential genetic mechanisms behind SS3

  16. Effects of calcium oxide treatment at varying moisture concentrations on the chemical composition, in situ degradability, in vitro digestibility and gas production kinetics of anaerobically stored corn stover.

    PubMed

    Shi, H T; Cao, Z J; Wang, Y J; Li, S L; Yang, H J; Bi, Y L; Doane, P H

    2016-08-01

    The objective of this study was to determine the optimum conditions for calcium oxide (CaO) treatment of anaerobically stored corn stover by in situ and in vitro methods. Four ruminally cannulated, non-lactating, non-pregnant Holstein cows were used to determine the in situ effective degradabilities of dry matter (ISDMD), organic matter (ISOMD), neutral detergent fibre (ISNDFD), in vitro organic matter disappearance (IVOMD) and gas production in 72 h (GP72h ) of corn stover. A completely randomized design involving a 3 × 3 factorial arrangement was adopted. Ground corn stover was treated with different levels of CaO (3%, 5% and 7% of dry stover) at varying moisture contents (40%, 50% and 60%) and stored under anaerobic conditions for 15 days before analysis. Compared with untreated corn stover, the CaO-treated stover had increased ash and calcium (Ca) contents but decreased aNDF and OM contents. The moisture content, CaO level and their interaction affected (p < 0.01) the content of aNDF, ash and OM, and the ratio of aNDF/OM. The greatest ISDMD, ISOMD and ISNDFD were observed when stover was treated with 7% CaO and 60% moisture, while no differences (p > 0.01) in these in situ degradability parameters were observed between the stover treated with 5% CaO at 60% moisture content and those treated with 7% CaO at 60% moisture content. Corn stover treated with 5% CaO at 50% moisture had the maximum IVOMD and GP72 h among the treatments, and there was no difference (p > 0.01) between 50% and 60% moisture. Results from this study suggested that 5% CaO applied at 60% moisture could be an effective and economical treatment combination. PMID:26300078

  17. Application of a slurry feeder to 1 and 3 stage continuous simultaneous saccharification and fermentation of dilute acid pretreated corn stover.

    PubMed

    Brethauer, Simone; Studer, Michael H; Wyman, Charles E

    2014-10-01

    Continuous operation is often chosen for conceptual designs of biological processing of cellulosic biomass to ethanol to achieve higher volumetric productivities. Furthermore, continuous stirred tank reactors (CSTR) can handle higher solids concentrations than possible in batch mode due to broth thinning at partial conversion in a continuous fermentor. However, experience and literature data are very limited for continuous simultaneous saccharification and fermentation (cSSF) processes. In this work, a slurry feed system was developed and applied to a 3-stage bench-scale cSSF train to convert pretreated corn stover to ethanol and determine the effects of dilution rate and number of fermentation vessels on overall volumetric productivity. The highest productivity of 0.4gL(-1)h(-1) was achieved in a single cSSF vessel with an 8h residence time. Furthermore, productivity at identical total residence times was 12% higher for operation with 3 cSSF stages than for a single CSTR stage for pretreated corn stover. PMID:25164339

  18. A two-stage pretreatment process using dilute hydrochloric acid followed by Fenton oxidation to improve sugar recovery from corn stover.

    PubMed

    Li, Wenzhi; Liu, Qiyu; Ma, Qiaozhi; Zhang, Tingwei; Ma, Longlong; Jameel, Hasan; Chang, Hou-Min

    2016-11-01

    A two-stage pretreatment process is proposed in this research in order to improve sugar recovery from corn stover. In the proposed process, corn stover is hydrolyzed by dilute hydrochloric acid to recover xylose, which is followed by a Fenton reagent oxidation to remove lignin. 0.7wt% dilute hydrochloric acid is applied in the first stage pretreatment at 120°C for 40min, resulting in 81.0% xylose removal. Fenton reagent oxidation (1g/L FeSO4·7H2O and 30g/L H2O2) is performed at room temperature (about 20°C) for 12 has a second stage which resulted in 32.9% lignin removal. The glucose yield in the subsequent enzymatic hydrolysis was 71.3% with a very low cellulase dosage (3FPU/g). This two-stage pretreatment is effective due to the hydrolysis of hemicelluloses in the first stage and the removal of lignin in the second stage, resulting in a very high sugar recovery with a low enzyme loading. PMID:27543312

  19. On-site enzymes produced from Trichoderma reesei RUT-C30 and Aspergillus saccharolyticus for hydrolysis of wet exploded corn stover and loblolly pine.

    PubMed

    Rana, Vandana; Eckard, Anahita D; Teller, Philip; Ahring, Birgitte K

    2014-02-01

    Cellulase production by two filamentous fungi Trichoderma reesei RUT-C30 and novel fungal strain, Aspergillus saccharolyticus on pretreated corn stover was investigated. Cellulase production was followed by the hydrolysis of two feedstocks, wet-exploded corn stover (WECS) and wet-exploded loblolly pine (WELP) by on-site produced enzyme cocktails containing cellulase from T. reesei RUT-C30 and β-glucosidase from A. saccharolyticus. The sugar yields using the on-site enzyme cocktails were compared with commercial enzymes preparations, Celluclast 1.5L and Novozym 188 at two substrate concentrations, 5% and 10% (w/w) and enzyme loading at 5 and 15 FPU/g glucan for WECS and WELP. The highest sugar yields were obtained at 5% (w/w) substrate concentration and 15 FPU/g glucan for both feedstocks. Glucose yields of 81% and 88% were obtained from on-site and commercial enzymes, respectively using WECS as feed stock. The sugar yields were 55% and 58% for WELP samples hydrolyzed with on-site and commercial enzymes, respectively. PMID:24412480

  20. 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

    SciTech Connect

    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.

  1. Kinetics of the pyrolysis of arundo, sawdust, corn stover and switch grass biomass by thermogravimetric analysis using a multi-stage model.

    PubMed

    Biney, Paul O; Gyamerah, Michael; Shen, Jiacheng; Menezes, Bruna

    2015-03-01

    A new multi-stage kinetic model has been developed for TGA pyrolysis of arundo, corn stover, sawdust and switch grass that accounts for the initial biomass weight (W0). The biomass were decomposed in a nitrogen atmosphere from 23°C to 900°C in a TGA at a single 20°C/min ramp rate in contrast with the isoconversion technique. The decomposition was divided into multiple stages based on the absolute local minimum values of conversion derivative, (dx/dT), obtained from DTG curves. This resulted in three decomposition stages for arundo, corn stover and sawdust and four stages for switch grass. A linearized multi-stage model was applied to the TGA data for each stage to determine the pre-exponential factor, activation energy, and reaction order. The activation energies ranged from 54.7 to 60.9 kJ/mol, 62.9 to 108.7 kJ/mol, and 18.4 to 257.9 kJ/mol for the first, second and the third decomposition stages respectively. PMID:25531683

  2. Simultaneous saccharification and co-fermentation of dry diluted acid pretreated corn stover at high dry matter loading: Overcoming the inhibitors by non-tolerant yeast.

    PubMed

    Zhu, Jia-Qing; Qin, Lei; Li, Wen-Chao; Zhang, Jian; Bao, Jie; Huang, Yao-Dong; Li, Bing-Zhi; Yuan, Ying-Jin

    2015-12-01

    Dry dilute acid pretreatment (DDAP) is a promising method for lignocellulose bioconversion, although inhibitors generated during the pretreatment impede the fermentation severely. We developed the simultaneous saccharification and co-fermentation (SScF) of DDAP pretreated biomass at high solid loading using xylose fermenting Saccharomyces cerevisiae, SyBE005. Effect of temperature on SScF showed that ethanol yield at 34°C was 10.2% higher than that at 38°C. Ethanol concentration reached 29.5 g/L at 15% (w/w) dry matter loading, while SScF almost ceased at the beginning at 25% (w/w) dry matter loading of DDAP pretreated corn stover. According to the effect of the diluted hydrolysate on the fermentation of strain SyBE005, a fed-batch mode was developed for the SScF of DDAP pretreated corn stover with 25% dry matter loading without detoxification, and 40.0 g/L ethanol was achieved. In addition, high yeast inoculation improved xylose utilization and the final ethanol concentration reached 47.2 g/L. PMID:26363500

  3. Effects of replacing wild rye, corn silage, or corn grain with CaO-treated corn stover and dried distillers grains with solubles in lactating cow diets on performance, digestibility, and profitability.

    PubMed

    Shi, H T; Li, S L; Cao, Z J; Wang, Y J; Alugongo, G M; Doane, P H

    2015-10-01

    The objective of this study was to measure the effects of partially replacing wild rye (Leymus chinensis; WR), corn silage (CS), or corn grain (CG) in dairy cow diets with CaO-treated corn stover (T-CS) and corn dried distillers grains with soluble (DDGS) on performance, digestibility, blood metabolites, and income over feed cost. Thirty tonnes of air-dried corn stover was collected, ground, and mixed with 5% CaO. Sixty-four Holstein dairy cows were blocked based on days in milk, milk yield, and parity and were randomly assigned to 1 of 4 treatments. The treatments were (1) a diet containing 50% concentrate, 15% WR, 25% CS, and 10% alfalfa hay (CON); (2) 15% WR, 5% CG, and 6% soybean meal were replaced by 15% T-CS and 12% DDGS (RWR); (3) 12.5% CS, 6% CG, and 5% soybean meal were replaced by 12.5% T-CS and 12%DDGS (RCS); (4) 13% CG and 6% soybean meal were replaced by 7% T-CS and 13% DDGS (RCG). Compared with CON treatment, cows fed RCS and RCG diets had similar dry matter intake (CON: 18.2 ± 0.31 kg, RCS: 18.6 ± 0.31 kg, and RCG: 18.4 ± 0.40 kg). The RWR treatment tended to have lower dry matter intake than other treatments. The inclusion of T-CS and DDGS in treatment diets as a substitute for WR, CS, or CG had no effects on lactose percentage (CON: 4.96 ± 0.02%, RWR: 4.97 ± 0.02%, RCS: 4.96 ± 0.02%, and RCG: 4.94 ± 0.02%), 4% fat-corrected milk yield (CON: 22.7 ± 0.60 kg, RWR: 22.1 ± 0.60 kg, RCS: 22.7 ± 0.60 kg, and RCG: 22.7 ± 0.60 kg), milk fat yield (CON: 0.90 ± 0.03 kg, RWR: 0.86 ± 0.03 kg, RCS: 0.87 ± 0.03 kg, and RCG: 0.89 ± 0.03 kg), and milk protein yield (CON: 0.74 ± 0.02 kg, RWR: 0.72 ± 0.02 kg, RCS: 0.73 ± 0.02 kg, and RCG: 0.71 ± 0.02 kg). Cows fed the RWR diet had higher apparent dry matter digestibility (73.7 ± 1.30 vs. 70.2 ± 1.15, 69.9 ± 1.15, and 69.9 ± 1.15% for RWR vs. CON, RCS, and RCG, respectively) and lower serum urea N (3.55 ± 0.11 vs. 4.03 ± 0.11, 3.95 ± 0.11, and 3.99 ± 0.11 mmol/L for RWR vs. CON, RCS, and RCG

  4. Single cell oil production by Mortierella isabellina from steam exploded corn stover degraded by three-stage enzymatic hydrolysis in the context of on-site enzyme production.

    PubMed

    Fang, Hao; Zhao, Chen; Chen, Shaolin

    2016-09-01

    Single cell oil (SCO), promising as alternative oil source, was produced from steam exploded corn stover (SECS) by Mortierella isabellina. Different bioprocesses from SECS to SCO were compared and the bioprocess C using the three-stage enzymatic hydrolysis was found to be the most efficient one. The bioprocess C used the lowest enzyme input 20FPIU cellulase/g glucan and the shortest time 222h, but produced 44.94g dry cell biomass and 25.77g lipid from 327.63g dry SECS. It had the highest lipid content 57.34%, and its productivities and yields were much higher than those of the bioprocess B and comparable to the bioprocess A, indicating that the three-stage enzymatic hydrolysis could greatly improve the efficiency of the bioprocess from high solid loading SECS to SCO by Mortierella isabellina. This work testified the application value of three-stage enzymatic hydrolysis in lignocellulose-based bioprocesses. PMID:27343451

  5. Pretreatment of corn stover for sugar production using a two-stage dilute acid followed by wet-milling pretreatment process.

    PubMed

    Liu, Qiyu; Li, Wenzhi; Ma, Qiaozhi; An, Shengxin; Li, Minghao; Jameel, Hasan; Chang, Hou-Min

    2016-07-01

    A two-stage process was evaluated to increase sugar recovery. Firstly, corn stover was treated with dilute hydrochloric acid to recover the xylose, and then the residue was subjected to a wet-milling pretreatment. Dilute hydrochloric acid showed a high xylose recovery during the first stage. The optimal condition was 120°C and 40min for 0.7wt% dilute hydrochloric acid pretreatment followed by wet-milling pretreatment for 15min. The xylose and glucose yield were 81.0% and 64.0%, respectively, with a cellulase dosage at 3FPU/g of substrate. This two-stage process was effective on account of the removal of hemicelluloses in the first stage and the delamination of cell wall in the second stage, increasing the possibility of adsorption of cellulose to enzymes, and resulting in a high sugar recovery with a very low enzyme loading. PMID:27035475

  6. Assessing the potential for increased capacity of combined heat and power facilities based on available corn stover and forest logging residue in Mississippi

    NASA Astrophysics Data System (ADS)

    Radhakrishnan, Selvarani

    The amount of available biomass feedstock and associated cost components were analyzed to determine the potential increase in energy capacity of two existing combined heat and power plants in Mississippi. The amount of corn stover and forest logging residue within a 10-mile radius can satisfy the existing requirements of CHP plants in Scott (1 MW) and Washington counties (5 MW). Transporting feedstock within a smaller source area had lower transportation costs, but higher total unit cost than the two other source buffer scenarios. However, capital costs associated with higher plant capacities were significantly higher and plant expansion may not be economically advantageous. Increasing the CHP capacity from 1 MW to 2 MW in Scott county and 5 MW to 10 MW in Washington county might be a sustainable approach by drawing feedstock from a smaller area and at lower utilization rates, while keeping transportation costs low.

  7. Corn stover semi-mechanistic enzymatic hydrolysis model with tight parameter confidence intervals for model-based process design and optimization.

    PubMed

    Scott, Felipe; Li, Muyang; Williams, Daniel L; Conejeros, Raúl; Hodge, David B; Aroca, Germán

    2015-02-01

    Uncertainty associated to the estimated values of the parameters in a model is a key piece of information for decision makers and model users. However, this information is typically not reported or the confidence intervals are too large to be useful. A semi-mechanistic model for the enzymatic saccharification of dilute acid pretreated corn stover is proposed in this work, the model is a modification of an existing one providing a statistically significant improved fit towards a set of experimental data that includes varying initial solid loadings (10-25% w/w) and the use of the pretreatment liquor and washed solids with or without supplementation of key inhibitors. A subset of 8 out of 17 parameters was identified, showing sufficiently tight confidence intervals to be used in uncertainty propagation and model analysis, without requiring interval truncation via expert judgment. PMID:25496946

  8. Evaluation of soluble fraction and enzymatic residual fraction of dilute dry acid, ethylenediamine, and steam explosion pretreated corn stover on the enzymatic hydrolysis of cellulose.

    PubMed

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

    2016-06-01

    This study is aimed to examine the inhibition of soluble fraction (SF) and enzymatic residual fraction (ERF) in dry dilute acid (DDA), ethylenediamine (EDA) and steam explosion (SE) pretreated corn stover (CS) on the enzymatic digestibility of cellulose. SF of DDA, EDA and SE pretreated CS has high xylose, soluble lignin and xylo-oligomer content, respectively. SF of EDA pretreated CS leads to the highest inhibition, followed by SE and DDA pretreated CS. Inhibition of ERF of DDA and SE pretreated CS is higher than that of EDA pretreated CS. The inhibition degree (A0/A) of SF is 1.76 and 1.21 times to that of ERF for EDA and SE pretreated CS, respectively. The inhibition degree of ERF is 1.05 times to that of SF in DDA pretreated CS. The quantitative analysis shows that SF of EDA pretreated CS, SF and ERF of SE pretreated CS cause significant inhibition during enzymatic hydrolysis. PMID:26970919

  9. Controlling microbial contamination during hydrolysis of AFEX-pretreated corn stover and switchgrass: Effects on hydrolysate composition, microbial response and fermentation

    SciTech Connect

    Serate, Jose; Xie, Dan; Pohlmann, Edward; Donald, Jr., Charles; Shabani, Mahboubeh; Hinchman, Li; Higbee, Alan; Mcgee, Mick; La Reau, Alex; Klinger, Grace E.; Li, Sheena; Myers, Chad L.; Boone, Charles; Bates, Donna M.; Cavalier, Dave; Eilert, Dustin; Oates, Lawrence G.; Sanford, Gregg; Sato, Trey K.; Dale, Bruce; Landick, Robert; Piotrowski, Jeff; Ong, Rebecca Garlock; Zhang, Yaoping

    2015-11-14

    Microbial conversion of lignocellulosic feedstocks into biofuels remains an attractive means to produce sustainable energy. It is essential to produce lignocellulosic hydrolysates in a consistent manner in order to study microbial performance in different feedstock hydrolysates. Because of the potential to introduce microbial contamination from the untreated biomass or at various points during the process, it can be difficult to control sterility during hydrolysate production. In this study, we compared hydrolysates produced from AFEX-pretreated corn stover and switchgrass using two different methods to control contamination: either by autoclaving the pretreated feedstocks prior to enzymatic hydrolysis, or by introducing antibiotics during the hydrolysis of non-autoclaved feedstocks. We then performed extensive chemical analysis, chemical genomics, and comparative fermentations to evaluate any differences between these two different methods used for producing corn stover and switchgrass hydrolysates. Autoclaving the pretreated feedstocks could eliminate the contamination for a variety of feedstocks, whereas the antibiotic gentamicin was unable to control contamination consistently during hydrolysis. Compared to the addition of gentamicin, autoclaving of biomass before hydrolysis had a minimal effect on mineral concentrations, and showed no significant effect on the two major sugars (glucose and xylose) found in these hydrolysates. However, autoclaving elevated the concentration of some furanic and phenolic compounds. Chemical genomics analyses using Saccharomyces cerevisiae strains indicated a high correlation between the AFEX-pretreated hydrolysates produced using these two methods within the same feedstock, indicating minimal differences between the autoclaving and antibiotic methods. Comparative fermentations with S. cerevisiae and Zymomonas mobilis also showed that autoclaving the AFEX-pretreated feedstocks had no significant effects on microbial performance in

  10. Controlling microbial contamination during hydrolysis of AFEX-pretreated corn stover and switchgrass: Effects on hydrolysate composition, microbial response and fermentation

    DOE PAGESBeta

    Serate, Jose; Xie, Dan; Pohlmann, Edward; Donald, Jr., Charles; Shabani, Mahboubeh; Hinchman, Li; Higbee, Alan; Mcgee, Mick; La Reau, Alex; Klinger, Grace E.; et al

    2015-11-14

    Microbial conversion of lignocellulosic feedstocks into biofuels remains an attractive means to produce sustainable energy. It is essential to produce lignocellulosic hydrolysates in a consistent manner in order to study microbial performance in different feedstock hydrolysates. Because of the potential to introduce microbial contamination from the untreated biomass or at various points during the process, it can be difficult to control sterility during hydrolysate production. In this study, we compared hydrolysates produced from AFEX-pretreated corn stover and switchgrass using two different methods to control contamination: either by autoclaving the pretreated feedstocks prior to enzymatic hydrolysis, or by introducing antibiotics duringmore » the hydrolysis of non-autoclaved feedstocks. We then performed extensive chemical analysis, chemical genomics, and comparative fermentations to evaluate any differences between these two different methods used for producing corn stover and switchgrass hydrolysates. Autoclaving the pretreated feedstocks could eliminate the contamination for a variety of feedstocks, whereas the antibiotic gentamicin was unable to control contamination consistently during hydrolysis. Compared to the addition of gentamicin, autoclaving of biomass before hydrolysis had a minimal effect on mineral concentrations, and showed no significant effect on the two major sugars (glucose and xylose) found in these hydrolysates. However, autoclaving elevated the concentration of some furanic and phenolic compounds. Chemical genomics analyses using Saccharomyces cerevisiae strains indicated a high correlation between the AFEX-pretreated hydrolysates produced using these two methods within the same feedstock, indicating minimal differences between the autoclaving and antibiotic methods. Comparative fermentations with S. cerevisiae and Zymomonas mobilis also showed that autoclaving the AFEX-pretreated feedstocks had no significant effects on microbial

  11. Enhanced alkaline cellulases production by the thermohalophilic Aspergillus terreus AUMC 10138 mutated by physical and chemical mutagens using corn stover as substrate

    PubMed Central

    Isaac, George Saad; Abu-Tahon, Medhat Ahmed

    2015-01-01

    Abstract A thermohalophilic fungus, Aspergillus terreus AUMC 10138, isolated from the Wadi El-Natrun soda lakes in northern Egypt was exposed successively to gamma and UV-radiation (physical mutagens) and ethyl methan-sulfonate (EMS; chemical mutagen) to enhance alkaline cellulase production under solid state fermentation (SSF) conditions. The effects of different carbon sources, initial moisture, incubation temperature, initial pH, incubation period, inoculum levels and different concentrations of NaCl on production of alkaline filter paper activity (FPase), carboxymethyl cellulase (CMCase) and β-glucosidase by the wild-type and mutant strains of A. terreus were evaluated under SSF. The optimum conditions for maximum production of FPase, CMCase and β-glucosidase were found to be the corn stover: moisture ratio of 1:3(w/v), temperature 45 °C, pH range, 9.0–11.0, and fermentation for 4, 4 and 7 day, respectively. Inoculum levels of 30% for β-glucosidase and 40% for FPase, CMCase gave the higher cellulase production by the wild-type and mutant strains, respectively. Higher production of all three enzymes was obtained at a 5% NaCl. Under the optimized conditions, the mutant strain A. terreus M-17 produced FPase (729 U/g), CMCase (1,783 U/g), and β-glucosidase (342 U/g), which is, 1.85, 1.97 and 2.31-fold higher than the wild-type strain. Our results confirmed that mutant strain M-17 could be a promising alkaline cellulase enzyme producer employing lignocellulosics especially corn stover. PMID:26691490

  12. Effect of mechanical disruption on the effectiveness of three reactors used for dilute acid pretreatment of corn stover Part 1: chemical and physical substrate analysis

    PubMed Central

    2014-01-01

    Background There is considerable interest in the conversion of lignocellulosic biomass to liquid fuels to provide substitutes for fossil fuels. Pretreatments, conducted to reduce biomass recalcitrance, usually remove at least some of the hemicellulose and/or lignin in cell walls. The hypothesis that led to this research was that reactor type could have a profound effect on the properties of pretreated materials and impact subsequent cellulose hydrolysis. Results Corn stover was dilute-acid pretreated using commercially relevant reactor types (ZipperClave® (ZC), Steam Gun (SG) and Horizontal Screw (HS)) under the same nominal conditions. Samples produced in the SG and HS achieved much higher cellulose digestibilities (88% and 95%, respectively), compared to the ZC sample (68%). Characterization, by chemical, physical, spectroscopic and electron microscopy methods, was used to gain an understanding of the effects causing the digestibility differences. Chemical differences were small; however, particle size differences appeared significant. Sum-frequency generation vibrational spectra indicated larger inter-fibrillar spacing or randomization of cellulose microfibrils in the HS sample. Simons’ staining indicated increased cellulose accessibility for the SG and HS samples. Electron microscopy showed that the SG and HS samples were more porous and fibrillated because of mechanical grinding and explosive depressurization occurring with these two reactors. These structural changes most likely permitted increased cellulose accessibility to enzymes, enhancing saccharification. Conclusions Dilute-acid pretreatment of corn stover using three different reactors under the same nominal conditions gave samples with very different digestibilities, although chemical differences in the pretreated substrates were small. The results of the physical and chemical analyses of the samples indicate that the explosive depressurization and mechanical grinding with these reactors increased

  13. Modeling the CO2 and N2O Emissions From Stover Removal for Biofuel Production From Continuous Corn Production in Iowa

    NASA Astrophysics Data System (ADS)

    Paustian, K.; Killian, K.; Brenner, J.

    2003-12-01

    Corn stover, an agricultural residue, can be used as feedstock for near term bioethanol production and is available today at levels that can significantly impact energy supply. We evaluated the environmental impact of such a large-scale change in agricultural practices on green house gas production, soil erosion and soil carbon using the Century model. Estimates of soil C changes and GHG emissions were performed for the 99 counties in Iowa where previous environmental, management and erosion data was available. We employed climate, soil and historical management databases from a separate USDA-funded project as input to Century. RUSLE estimates of the residue requirements for acceptable soil loss rates under continuous corn agriculture were available from a previous study done Dr. Richard Nelson (Enersol Resources). Two mulch tillage and a no-till systems, where erosion estimates were available, were used as the basis for the simulations. Century simulations of these systems were run under a variety of stover removal rates. For each soil type within each county the model was run for 15 years (1980-1995) under continuous corn with convention tillage, and full residue return. Model simulation of crop yields and residue production were then calibrated to match those used by the Polysys model team at Oak Ridge and the simulation was repeated with the addition of the three corn tillage regimes, and several residue removal rates. County-average soil C changes (and net CO2 emissions) were calculated as area-weighted averages of the individual soil types in each county. For this study, we have utilized the IPCC approach to estimate annual N2O emissions. At low or zero residue removal rates, county-averaged soil C stocks were predicted to increase (i.e. net CO2 emissions are negative). Where the allowable residue removal rates (based on erosion tolerance) for mulch-tillage are on the order of 40-50% or more, the reduced input of C is such that the soils no longer sequester C

  14. High-titer lactic acid production from NaOH-pretreated corn stover by Bacillus coagulans LA204 using fed-batch simultaneous saccharification and fermentation under non-sterile condition.

    PubMed

    Hu, Jinlong; Zhang, Zhenting; Lin, Yanxu; Zhao, Shumiao; Mei, Yuxia; Liang, Yunxiang; Peng, Nan

    2015-04-01

    Lactic acid (LA) is an important chemical with various industrial applications. Non-food feedstock is commercially attractive for use in LA production; however, efficient LA fermentation from lignocellulosic biomass resulting in both high yield and titer faces technical obstacles. In this study, the thermophilic bacterium Bacillus coagulans LA204 demonstrated considerable ability to ferment glucose, xylose, and cellobiose to LA. Importantly, LA204 produces LA from several NaOH-pretreated agro stovers, with remarkably high yields through simultaneous saccharification and fermentation (SSF). A fed-batch SSF process conducted at 50°C and pH 6.0, using a cellulase concentration of 30 FPU (filter paper unit)/g stover and 10 g/L yeast extract in a 5-L bioreactor, was developed to produce LA from 14.4% (w/w) NaOH-pretreated non-sterile corn stover. LA titer, yield, and average productivity reached 97.59 g/L, 0.68 g/g stover, and 1.63 g/L/h, respectively. This study presents a feasible process for lignocellulosic LA production from abundant agro stovers. PMID:25704098

  15. Effects of twenty percent alkaline-treated corn stover without or with yucca extract on performance and nutrient mass balance of finishing steers fed modified distillers grains-based diets.

    PubMed

    Johnson, J M; Shreck, A L; Nuttelman, B L; Burken, D B; Erickson, G E; Rincker, M J; Cecava, M J; Klopfenstein, T J

    2015-06-01

    Two experiments were conducted with 192 steers each (during the winter [November to May] or summer [June to October]) to evaluate 3 diets with or without Yucca schidigera extract in a 3 × 2 factorial on steer growth performance and N mass balance. One factor was diet (DM basis): 1) 5% untreated corn stover, 51% corn, and 40% modified distillers grains plus solubles (MDGS; CON); 2) 20% calcium oxide-treated corn stover (CaO added at 5% of stover DM), 40% MDGS, and 36% corn (TRT); or 3) 20% untreated corn stover, 40% MDGS, and 36% corn (NONTRT). The other factor was dietary extract at 0 (NOYE) or 1.0 g/d per steer (YE). No interaction between diet and YE was detected (P > 0.51) for growth performance and carcass traits in winter and only for DMI in summer. Final BW, ADG, DMI, or G:F were not different (P ≥ 0.28) between cattle fed CON and TRT, whereas cattle fed NONTRT had lesser ADG, HCW, and G:F compared to CON and TRT in the winter experiment. During the summer, final BW and ADG tended to be greater (P ≥ 0.07) for CON compared to TRT. Cattle fed TRT had reduced (P < 0.01) G:F compared to CON. No difference was observed (P ≥ 0.36) between YE and NOYE in the winter experiment for performance or carcass traits. In the summer, cattle fed YE had greater (P < 0.02) HCW, ADG, and DMI compared to NOYE. In the summer experiment, cattle fed YE had greater (P < 0.01) N intake, N excretion, and amount of N lost (kg/steer) compared to NOYE, but no difference (P = 0.33) was observed for percentage of N volatilized (% of excretion). Diet had no effect (P > 0.18) on amount (kg/steer) or percentage of N volatized in the winter or summer. All diets had similar amounts (P > 0.13) of DM and OM removed from the pen surface in both summer and winter. Feeding CaO-treated corn stover as a partial grain replacement had no impact on performance in winter but decreased G:F in summer. Although high-fiber diets increased the amount of OM on pen surfaces, they did not impact N

  16. Fermentative production of high titer gluconic and xylonic acids from corn stover feedstock by Gluconobacter oxydans and techno-economic analysis.

    PubMed

    Zhang, Hongsen; Liu, Gang; Zhang, Jian; Bao, Jie

    2016-11-01

    High titer gluconic acid and xylonic acid were simultaneously fermented by Gluconobacter oxydans DSM 2003 using corn stover feedstock after dry dilute sulfuric acid pretreatment, biodetoxification and high solids content hydrolysis. Maximum sodium gluconate and xylonate were produced at the titer of 132.46g/L and 38.86g/L with the overall yield of 97.12% from glucose and 90.02% from xylose, respectively. The drawbacks of filamentous fungus Aspergillus niger including weak inhibitor tolerance, large pellet formation and no xylose utilization were solved by using the bacterium strain G. oxydans. The obtained sodium gluconate/xylonate product was highly competitive as cement retarder additive to the commercial product from corn feedstock. The techno-economic analysis (TEA) based on the Aspen Plus modeling was performed and the minimum sodium gluconate/xylonate product selling price (MGSP) was calculated as $0.404/kg. This study provided a practical and economic competitive process of lignocellulose utilization for production of value-added biobased chemicals. PMID:27484668

  17. Pretreatment of Corn Stover by Low Moisture Anhydrous Ammonia (LMAA) in a Pilot-Scale Reactor and Bioconversion to Fuel Ethanol and Industrial Chemicals.

    PubMed

    Nghiem, Nhuan P; Senske, Gerard E; Kim, Tae Hyun

    2016-04-01

    Corn stover (CS) adjusted to 50, 66, and 70 % moisture was pretreated by the low moisture anhydrous ammonia (LMAA) process in a pilot-scale ammoniation reactor. After ammoniation, the 70 % moisture CS was treated at 90 and 100 °C whereas the others were treated at 90 °C only. The 70 % moisture pretreated CS then was subjected to a storage study under non-sterile conditions for 3 months. It was found that storage time did not have significant effects on the compositions of the pretreated materials and their hydrolysis by commercial enzymes. The 70 % moisture CS treated at 90 °C was used for preparation of a mix sugar hydrolysate (MSH) using combination of cellulase and xylanase. The MSH was used to prepare a corn mash at 9.5 wt% solid then subjected to ethanol fermentation by Escherichia coli KO11. The 66 % moisture CS treated at 90 °C was hydrolyzed with xylanase to make a xylose-rich hydrolysate (XRH), which was subsequently used for butyric acid fermentation by Clostridium tyrobutyricum. The resultant cellulose-enriched residue was hydrolyzed with cellulase to make a glucose-rich hydrolysate (GRH), which was subsequently used for succinic acid fermentation by E. coli AFP184. PMID:26769706

  18. Biobased polymer composites derived from corn stover and feather meals as double-coating materials for controlled-release and water-retention urea fertilizers.

    PubMed

    Yang, Yuechao; Tong, Zhaohui; Geng, Yuqing; Li, Yuncong; Zhang, Min

    2013-08-28

    In this paper, we synthesized a biobased polyurethane using liquefied corn stover, isocyanate, and diethylenetriamine. The synthesized polyurethane was used as a coating material to control nitrogen (N) release from polymer-coated urea. A novel superabsorbent composite was also formulated from chicken feather protein (CFP), acrylic acid, and N,N'-methylenebisacrylamide and used as an outer coating material for water retention. We studied the N release characteristics and water-retention capability of the double-layer polymer-coated urea (DPCU) applied in both water and soils. The ear yields, dry matter accumulation, total N use efficiency and N leaching from a sweet corn soil-plant system under two different irrigation regimes were also investigated. Comparison of DPCU treatments with conventional urea fertilizer revealed that DPCU treatments reduced the N release rate and improved water retention capability. Evaluation of soil and plant characteristics within the soil-plant system revealed that DPCU application effectively reduced N leaching loss, improved total N use efficiency, and increased soil water retention capability. PMID:23923819

  19. Cellulosic Biomass Sugars to Advantage Jet Fuel: Catalytic Conversion of Corn Stover to Energy Dense, Low Freeze Point Paraffins and Naphthenes: Cooperative Research and Development Final Report, CRADA Number CRD-12-462

    SciTech Connect

    Elander, Rick

    2015-08-04

    NREL will provide scientific and engineering support to Virent Energy Systems in three technical areas: Process Development/Biomass Deconstruction; Catalyst Fundamentals; and Technoeconomic Analysis. The overarching objective of this project is to develop the first fully integrated process that can convert a lignocellulosic feedstock (e.g., corn stover) efficiently and cost effectively to a mix of hydrocarbons ideally suited for blending into jet fuel. The proposed project will investigate the integration of Virent Energy System’s novel aqueous phase reforming (APR) catalytic conversion technology (BioForming®) with deconstruction technologies being investigated by NREL at the 1-500L scale. Corn stover was chosen as a representative large volume, sustainable feedstock.

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

    SciTech Connect

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

    2002-06-01

    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.

  1. Engineering and two-stage evolution of a lignocellulosic hydrolysate-tolerant Saccharomyces cerevisiae strain for anaerobic fermentation of xylose from AFEX pretreated corn stover.

    PubMed

    Parreiras, Lucas S; Breuer, Rebecca J; Avanasi Narasimhan, Ragothaman; Higbee, Alan J; La Reau, Alex; Tremaine, Mary; Qin, Li; Willis, Laura B; Bice, Benjamin D; Bonfert, Brandi L; Pinhancos, Rebeca C; Balloon, Allison J; Uppugundla, Nirmal; Liu, Tongjun; Li, Chenlin; Tanjore, Deepti; Ong, Irene M; Li, Haibo; Pohlmann, Edward L; Serate, Jose; Withers, Sydnor T; Simmons, Blake A; Hodge, David B; Westphall, Michael S; Coon, Joshua J; Dale, Bruce E; Balan, Venkatesh; Keating, David H; Zhang, Yaoping; Landick, Robert; Gasch, Audrey P; Sato, Trey K

    2014-01-01

    The inability of the yeast Saccharomyces cerevisiae to ferment xylose effectively under anaerobic conditions is a major barrier to economical production of lignocellulosic biofuels. Although genetic approaches have enabled engineering of S. cerevisiae to convert xylose efficiently into ethanol in defined lab medium, few strains are able to ferment xylose from lignocellulosic hydrolysates in the absence of oxygen. This limited xylose conversion is believed to result from small molecules generated during biomass pretreatment and hydrolysis, which induce cellular stress and impair metabolism. Here, we describe the development of a xylose-fermenting S. cerevisiae strain with tolerance to a range of pretreated and hydrolyzed lignocellulose, including Ammonia Fiber Expansion (AFEX)-pretreated corn stover hydrolysate (ACSH). We genetically engineered a hydrolysate-resistant yeast strain with bacterial xylose isomerase and then applied two separate stages of aerobic and anaerobic directed evolution. The emergent S. cerevisiae strain rapidly converted xylose from lab medium and ACSH to ethanol under strict anaerobic conditions. Metabolomic, genetic and biochemical analyses suggested that a missense mutation in GRE3, which was acquired during the anaerobic evolution, contributed toward improved xylose conversion by reducing intracellular production of xylitol, an inhibitor of xylose isomerase. These results validate our combinatorial approach, which utilized phenotypic strain selection, rational engineering and directed evolution for the generation of a robust S. cerevisiae strain with the ability to ferment xylose anaerobically from ACSH. PMID:25222864

  2. Engineering wild-type robust Pediococcus acidilactici strain for high titer L- and D-lactic acid production from corn stover feedstock.

    PubMed

    Yi, Xia; Zhang, Peng; Sun, Jiaoe; Tu, Yi; Gao, Qiuqiang; Zhang, Jian; Bao, Jie

    2016-01-10

    Pediococcus acidilactici TY112 producing L-lactic acid and P. acidilactici ZP26 producing D-lactic acid, were engineered from the wild-type P. acidilactici DQ2 by ldhD or ldh gene disruption, and the robustness of the wild-type strain to the inhibitors derived from lignocellulose pretreatment was maintained well. In simultaneous saccharification and fermentation (SSF), 77.66 g L(-1) of L-lactic acid and 76.76 g L(-1) of D-lactic acid were obtained at 25% (w/w) solids content of dry dilute acid pretreated and biodetoxified corn stover feedstock. L- and D-Lactic acid yield and productivity were highly dependent on the inhibitor removal extent due to the significant down-regulation on the expressions of ldh and ldhD encoding lactate dehydrogenase by inhibitor, especially syringaldehyde and vanillin at the low concentrations. This study provided a prototype of industrial process for high titer L- and D-lactic acid production from lignocellulose feedstock. PMID:26616423

  3. Comparison of different liquid anaerobic digestion effluents as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover.

    PubMed

    Xu, Fuqing; Shi, Jian; Lv, Wen; Yu, Zhongtang; Li, Yebo

    2013-01-01

    Effluents from three liquid anaerobic digesters, fed with municipal sewage sludge, food waste, or dairy waste, were evaluated as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover in mesophilic reactors. Three feedstock-to-effluent (F/E) ratios (i.e., 2, 4, and 6) were tested for each effluent. At an F/E ratio of 2, the reactor inoculated by dairy waste effluent achieved the highest methane yield of 238.5L/kg VS(feed), while at an F/E ratio of 4, the reactor inoculated by food waste effluent achieved the highest methane yield of 199.6L/kg VS(feed). The microbial population and chemical composition of the three effluents were substantially different. Food waste effluent had the largest population of acetoclastic methanogens, while dairy waste effluent had the largest populations of cellulolytic and xylanolytic bacteria. Dairy waste also had the highest C/N ratio of 8.5 and the highest alkalinity of 19.3g CaCO(3)/kg. The performance of solid-state batch anaerobic digestion reactors was closely related to the microbial status in the liquid anaerobic digestion effluents. PMID:22958949

  4. Phytotoxicity assessment on corn stover biochar, derived from fast pyrolysis, based on seed germination, early growth, and potential plant cell damage.

    PubMed

    Li, Yang; Shen, Fei; Guo, Haiyan; Wang, Zhanghong; Yang, Gang; Wang, Lilin; Zhang, Yanzong; Zeng, Yongmei; Deng, Shihuai

    2015-06-01

    The potential phytotoxicity of water extractable toxicants in a typical corn stover biochar, the product of fast pyrolysis, was investigated using an aqueous biochar extract on a soil-less bioassay with tomato plants. The biochar dosage of 0.0-16.0 g beaker(-1) resulted in an inverted U-shaped dose-response relationship between biochar doasage and seed germination/seedling growth. This indicated that tomato growth was slightly stimulated by low dosages of biochar and inhibited with higher dosages of biochar. Additionally, antioxidant enzyme activities in the roots and leaves were enhanced at lower dosages, but rapidly decreased with higher dosages of biochar. With the increased dosages of biochar, the malondialdehyde content in the roots and leaves increased, in addition with the observed morphology of necrotic root cells, suggesting that serious damage to tomato seedlings occurred. EC50 of root length inhibition occurred with biochar dosages of 9.2 g beaker(-1) (3.5th day) and 16.7 g beaker(-1) (11th day) (equivalent to 82.8 and 150.3 t ha(-1), respectively), which implied that toxicity to the early growth of tomato can potentially be alleviated as the plant grows. PMID:25628114

  5. Defined enzyme cocktail from the anaerobic fungus Orpinomyces sp. strain C1A effectively releases sugars from pretreated corn stover and switchgrass.

    PubMed

    Morrison, Jessica M; Elshahed, Mostafa S; Youssef, Noha H

    2016-01-01

    The anaerobic fungus Orpinomyces strain C1A is capable of growth on various types of lignocellulosic substrates, and harbors an impressive reservoir of carbohydrate active enzymes (CAZymes). Using a minimum enzyme cocktail strategy, we constituted a four-component lignocellulolytic cocktail derived from highly transcribed C1A, and evaluated its efficacy against pretreated corn stover and switchgrass. Hydrolysis yields ranged between 65-77.4%, depending on the lignocellulosic substrate and pretreatment applied. Addition of a highly expressed anaerobic fungal swollenin improved hydrolysis yields by up to 7%. Compared to the commercial cocktail CTec2, these anaerobic fungal cocktails provided comparable or slightly lower hydrolysis yields. Further, the differences in efficacy between commercial and anaerobic cocktails were often only realized after extended (168 hr) incubations. Under certain conditions, the hydrolysis yields of the anaerobic fungal cocktail was slightly superior to that realized by CTec2. We attribute the observed high hydrolysis yields to the high specific activity and affinity of the individual enzymes of the cocktail, as well as the high level of synergy and multi-functionality observed in multiple components. Collectively, this effort provides a novel platform for constructing highly effective enzymes for biofuel production and represents the first lignocellulolytic enzyme cocktail created from anaerobic fungal enzymes. PMID:27381262

  6. Genetic engineering and improvement of a Zymomonas mobilis for arabinose utilization and its performance on pretreated corn stover hydrolyzate

    SciTech Connect

    Chou, Yat -Chen; Linger, Jeffrey; Yang, Shihui; Zhang, Min

    2015-04-28

    In this paper, a glucose, xylose and arabinose utilizing Zymomonas mobilis strain was constructed by incorporating arabinose catabolic pathway genes, araBAD encoding L-ribulokinase, L-arabinose isomerase and L-ribulose-5-phosphate- 4-epimerase in a glucose, xylose co-fermenting host, 8b, using a transposition integration approach. Further improvement on this arabinose-capable integrant, 33C was achieved by applying a second transposition to create a genomic knockout (KO) mutant library. Using arabinose as a sole carbon source and a selection pressure, the KO library was subjected to a growth-enrichment process involving continuous sub-culturing for over 120 generations. Strain 13-1-17, isolated from such process demonstrated significant improvement in metabolizing arabinose in a dilute acid pretreated, saccharified corn stover slurry. Through Next Generation Sequencing (NGS) analysis, integration sites of the transposons were identified. Furthermore, multiple additional point mutations (SNPs: Single Nucleotide Polymorphisms) were discovered in 13-1-17, affecting genes araB and RpiB in the genome. Finally, we speculate that these mutations may have impacted the expression of the enzymes coded by these genes, ribulokinase and Ribose 5-P-isomerase, thus attributing to the improvement of the arabinose utilization.

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

    SciTech Connect

    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 $2.15/gal in 2007$.

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

    SciTech Connect

    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.

  9. Engineering and Two-Stage Evolution of a Lignocellulosic Hydrolysate-Tolerant Saccharomyces cerevisiae Strain for Anaerobic Fermentation of Xylose from AFEX Pretreated Corn Stover

    PubMed Central

    Parreiras, Lucas S.; Breuer, Rebecca J.; Avanasi Narasimhan, Ragothaman; Higbee, Alan J.; La Reau, Alex; Tremaine, Mary; Qin, Li; Willis, Laura B.; Bice, Benjamin D.; Bonfert, Brandi L.; Pinhancos, Rebeca C.; Balloon, Allison J.; Uppugundla, Nirmal; Liu, Tongjun; Li, Chenlin; Tanjore, Deepti; Ong, Irene M.; Li, Haibo; Pohlmann, Edward L.; Serate, Jose; Withers, Sydnor T.; Simmons, Blake A.; Hodge, David B.; Westphall, Michael S.; Coon, Joshua J.; Dale, Bruce E.; Balan, Venkatesh; Keating, David H.; Zhang, Yaoping; Landick, Robert; Gasch, Audrey P.; Sato, Trey K.

    2014-01-01

    The inability of the yeast Saccharomyces cerevisiae to ferment xylose effectively under anaerobic conditions is a major barrier to economical production of lignocellulosic biofuels. Although genetic approaches have enabled engineering of S. cerevisiae to convert xylose efficiently into ethanol in defined lab medium, few strains are able to ferment xylose from lignocellulosic hydrolysates in the absence of oxygen. This limited xylose conversion is believed to result from small molecules generated during biomass pretreatment and hydrolysis, which induce cellular stress and impair metabolism. Here, we describe the development of a xylose-fermenting S. cerevisiae strain with tolerance to a range of pretreated and hydrolyzed lignocellulose, including Ammonia Fiber Expansion (AFEX)-pretreated corn stover hydrolysate (ACSH). We genetically engineered a hydrolysate-resistant yeast strain with bacterial xylose isomerase and then applied two separate stages of aerobic and anaerobic directed evolution. The emergent S. cerevisiae strain rapidly converted xylose from lab medium and ACSH to ethanol under strict anaerobic conditions. Metabolomic, genetic and biochemical analyses suggested that a missense mutation in GRE3, which was acquired during the anaerobic evolution, contributed toward improved xylose conversion by reducing intracellular production of xylitol, an inhibitor of xylose isomerase. These results validate our combinatorial approach, which utilized phenotypic strain selection, rational engineering and directed evolution for the generation of a robust S. cerevisiae strain with the ability to ferment xylose anaerobically from ACSH. PMID:25222864

  10. Defined enzyme cocktail from the anaerobic fungus Orpinomyces sp. strain C1A effectively releases sugars from pretreated corn stover and switchgrass

    PubMed Central

    Morrison, Jessica M.; Elshahed, Mostafa S.; Youssef, Noha H.

    2016-01-01

    The anaerobic fungus Orpinomyces strain C1A is capable of growth on various types of lignocellulosic substrates, and harbors an impressive reservoir of carbohydrate active enzymes (CAZymes). Using a minimum enzyme cocktail strategy, we constituted a four-component lignocellulolytic cocktail derived from highly transcribed C1A, and evaluated its efficacy against pretreated corn stover and switchgrass. Hydrolysis yields ranged between 65–77.4%, depending on the lignocellulosic substrate and pretreatment applied. Addition of a highly expressed anaerobic fungal swollenin improved hydrolysis yields by up to 7%. Compared to the commercial cocktail CTec2, these anaerobic fungal cocktails provided comparable or slightly lower hydrolysis yields. Further, the differences in efficacy between commercial and anaerobic cocktails were often only realized after extended (168 hr) incubations. Under certain conditions, the hydrolysis yields of the anaerobic fungal cocktail was slightly superior to that realized by CTec2. We attribute the observed high hydrolysis yields to the high specific activity and affinity of the individual enzymes of the cocktail, as well as the high level of synergy and multi-functionality observed in multiple components. Collectively, this effort provides a novel platform for constructing highly effective enzymes for biofuel production and represents the first lignocellulolytic enzyme cocktail created from anaerobic fungal enzymes. PMID:27381262

  11. Stover removal and cover crops effects on corn production and water use under full and limited irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) residue removal in irrigated cropping systems for livestock forage or cellulosic ethanol is of great interest in south-central Nebraska. Irrigation water restrictions in the region have also resulted in adoption of limited-irrigation strategies. Little is known regarding the inter...

  12. Reduced ferulate cross link concentration is associated with improved fiber digestibility of corn stover at silage maturity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ferulate cross linking of lignin to arabinoxylan is correlated with fiber digestibility in perennial cool-season grasses; however, similar data have not been reported for warm-season grasses. Our objective was to determine if ferulate cross links are associated with fiber digestibility in corn stove...

  13. Anaerobic and sequential aerobic production of high-titer ethanol and single cell protein from NaOH-pretreated corn stover by a genome shuffling-modified Saccharomyces cerevisiae strain.

    PubMed

    Ren, Xueliang; Wang, Juncong; Yu, Hui; Peng, Chunlan; Hu, Jinlong; Ruan, Zhiyong; Zhao, Shumiao; Liang, Yunxiang; Peng, Nan

    2016-10-01

    In this study, a Saccharomyces cerevisiae recombinant strain 14 was constructed through genome shuffling method by transferring the whole genomic DNA of Candida intermedia strain 23 into a thermo-tolerant S. cerevisiae strain. The recombinant strain 14 combined the good natures of both parent strains that efficiently produced ethanol from glucose and single cell protein from xylose with 54.6% crude protein and all essential amino acids except cysteine at 35°C. Importantly, the recombinant strain 14 produced 64.07g/L ethanol from 25%(w/v) NaOH-pretreated and washed corn stover with the ethanol yield of 0.26g/g total stover by fed-batch simultaneous saccharification and fermentation and produced 66.50g/L dry cell mass subsequently from the residual hydrolysate and ethanol. Therefore, this study represents a feasible method to comprehensively utilize hexose and pentose in lignocellulosic materials. PMID:27416512

  14. Comparison of SHF and SSF of wet exploded corn stover and loblolly pine using in-house enzymes produced from T. reesei RUT C30 and A. saccharolyticus.

    PubMed

    Rana, Vandana; Eckard, Anahita D; Ahring, Birgitte K

    2014-01-01

    The aim of the present study was to compare bioethanol production from wet exploded corn stover (WECS) and loblolly pine (WELP) hydrolyzed with in-house and commercial enzymes and fermented separately (SHF) and simultaneously (SSF). In-house enzymes produced from Trichoderma reesei, RUT-C30 and a novel fungal strain, Aspergillus saccharolyticus were loaded as 5 and 15 FPU/g glucan and supplemented with 10 and 30 CBU/g glucan, respectively. For hydrolysis and fermentation, slurries of WECS and WELP at 5 and 10% (w/w) solids loading (SL) were utilized. Saccharomyces cerevisae was used for ethanol fermentation at 33°C. Maximally, 15.6 g/L and 13.4 g/L (corresponding to theoretical ethanol yield of 76% and 67%, respectively) were achieved in SSF process from WECS and WELP, respectively at 5% SL and 15 FPU/g glucan loading of in-house enzymes. Ethanol concentrations in all cases were higher for SSF compared to SHF under same conditions. A cross comparison of SSF with commercial enzymes (Celluclast 1.5 L + Novozym 188) showed highest ethanol concentration of 17.3 g/L and 15.4 g/L (corresponding to theoretical ethanol yield of 84% and 77%, respectively) from WECS and WELP, respectively at 5% SL and 15 FPU/g glucan. These findings demonstrated that in-house enzymes were comparable to commercial enzymes as these fungi produced other lignocellulolytic enzymes beyond cellulase and hence enhanced the overall enzyme activity. PMID:25279308

  15. Comparison of different liquid anaerobic digestion effluents as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover

    SciTech Connect

    Xu Fuqing; Shi Jian; Lv Wen; Yu Zhongtang; Li Yebo

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Compared methane production of solid AD inoculated with different effluents. Black-Right-Pointing-Pointer Food waste effluent (FWE) had the largest population of acetoclastic methanogens. Black-Right-Pointing-Pointer Solid AD inoculated with FWE produced the highest methane yield at F/E ratio of 4. Black-Right-Pointing-Pointer Dairy waste effluent (DWE) was rich of cellulolytic and xylanolytic bacteria. Black-Right-Pointing-Pointer Solid AD inoculated with DWE produced the highest methane yield at F/E ratio of 2. - Abstract: Effluents from three liquid anaerobic digesters, fed with municipal sewage sludge, food waste, or dairy waste, were evaluated as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover in mesophilic reactors. Three feedstock-to-effluent (F/E) ratios (i.e., 2, 4, and 6) were tested for each effluent. At an F/E ratio of 2, the reactor inoculated by dairy waste effluent achieved the highest methane yield of 238.5 L/kgVS{sub feed}, while at an F/E ratio of 4, the reactor inoculated by food waste effluent achieved the highest methane yield of 199.6 L/kgVS{sub feed}. The microbial population and chemical composition of the three effluents were substantially different. Food waste effluent had the largest population of acetoclastic methanogens, while dairy waste effluent had the largest populations of cellulolytic and xylanolytic bacteria. Dairy waste also had the highest C/N ratio of 8.5 and the highest alkalinity of 19.3 g CaCO{sub 3}/kg. The performance of solid-state batch anaerobic digestion reactors was closely related to the microbial status in the liquid anaerobic digestion effluents.

  16. Effect of mechanical disruption on the effectiveness of three reactors used for dilute acid pretreatment of corn stover Part 2: morphological and structural substrate analysis

    PubMed Central

    2014-01-01

    Background Lignocellulosic biomass is a renewable, naturally mass-produced form of stored solar energy. Thermochemical pretreatment processes have been developed to address the challenge of biomass recalcitrance, however the optimization, cost reduction, and scalability of these processes remain as obstacles to the adoption of biofuel production processes at the industrial scale. In this study, we demonstrate that the type of reactor in which pretreatment is carried out can profoundly alter the micro- and nanostructure of the pretreated materials and dramatically affect the subsequent efficiency, and thus cost, of enzymatic conversion of cellulose. Results Multi-scale microscopy and quantitative image analysis was used to investigate the impact of different biomass pretreatment reactor configurations on plant cell wall structure. We identify correlations between enzymatic digestibility and geometric descriptors derived from the image data. Corn stover feedstock was pretreated under the same nominal conditions for dilute acid pretreatment (2.0 wt% H2SO4, 160°C, 5 min) using three representative types of reactors: ZipperClave® (ZC), steam gun (SG), and horizontal screw (HS) reactors. After 96 h of enzymatic digestion, biomass treated in the SG and HS reactors achieved much higher cellulose conversions, 88% and 95%, respectively, compared to the conversion obtained using the ZC reactor (68%). Imaging at the micro- and nanoscales revealed that the superior performance of the SG and HS reactors could be explained by reduced particle size, cellular dislocation, increased surface roughness, delamination, and nanofibrillation generated within the biomass particles during pretreatment. Conclusions Increased cellular dislocation, surface roughness, delamination, and nanofibrillation revealed by direct observation of the micro- and nanoscale change in accessibility explains the superior performance of reactors that augment pretreatment with physical energy. PMID:24690534

  17. Difference analysis of the enzymatic hydrolysis performance of acid-catalyzed steam-exploded corn stover before and after washing with water.

    PubMed

    Zhu, Junjun; Shi, Linli; Zhang, Lingling; Xu, Yong; Yong, Qiang; Ouyang, Jia; Yu, Shiyuan

    2016-10-01

    The difference in the enzymatic hydrolysis yield of acid-catalyzed steam-exploded corn stover (ASC) before and after washing with water reached approximately 15 % under the same conditions. The reasons for the difference in the yield between ASC and washed ASC (wASC) were determined through the analysis of the composition of ASC prehydrolyzate and sugar concentration of enzymatic hydrolyzate. Salts produced by neutralization (CaSO4, Na2SO4, K2SO4, and (NH4)2SO4), sugars (polysaccharides, oligosaccharides, and monosaccharides), sugar-degradation products (weak acids and furans), and lignin-degradation products (ethyl acetate extracts and nine main lignin-degradation products) were back-added to wASC. Results showed that these products, except furans, exerted negative effect on enzymatic hydrolysis. According to the characteristics of acid-catalyzed steam explosion pretreatment, the five sugar-degradation products' mixture and salts [Na2SO4, (NH4)2SO4] showed minimal negative inhibition effect on enzymatic hydrolysis. By contrast, furans demonstrated a promotion effect. Moreover, soluble sugars, such as 13 g/L xylose (decreased by 6.38 %), 5 g/L cellobiose (5.36 %), 10 g/L glucose (3.67 %), as well as lignin-degradation products, and ethyl acetate extracts (4.87 %), exhibited evident inhibition effect on enzymatic hydrolysis. Therefore, removal of soluble sugars and lignin-degradation products could effectively promote the enzymatic hydrolysis performance. PMID:27277746

  18. [Corn.

    ERIC Educational Resources Information Center

    Iowa History for Young People, 1993

    1993-01-01

    This theme issue focuses on corn. Iowa is the number one corn producing state in the United States. The featured articles in the issue concern, among other topics, Iowa children who live on farms, facts and statistics about corn, the Mesquakie Indians and corn shelling, corn hybrids, a short story, and the corn palaces of Sioux City. Activities,…

  19. DMR (deacetylation and mechanical refining) processing of corn stover achieves high monomeric sugar concentrations (230 g L-1) during enzymatic hydrolysis and high ethanol concentrations (>10% v/v) during fermentation without hydrolysate purification or concentration

    DOE PAGESBeta

    Chen, Xiaowen; Kuhn, Erik; Jennings, Edward W.; Nelson, Robert; Tao, Ling; Zhang, Min; Tucker, Melvin P.

    2016-04-01

    Distilling and purifying ethanol and other products from second generation lignocellulosic biorefineries adds significant capital and operating costs to biofuel production. The energy usage associated with distillation negatively affects plant gate costs and causes environmental and life-cycle impacts, and the lower titers in fermentation caused by lower sugar concentrations from pretreatment and enzymatic hydrolysis increase energy and water usage and ethanol production costs. In addition, lower ethanol titers increase the volumes required for enzymatic hydrolysis and fermentation vessels increase capital expenditure (CAPEX). Therefore, increasing biofuel titers has been a research focus in renewable biofuel production for several decades. In thismore » work, we achieved approximately 230 g L-1 of monomeric sugars after high solid enzymatic hydrolysis using deacetylation and mechanical refining (DMR) processed corn stover substrates produced at the 100 kg per day scale. The high sugar concentrations and low chemical inhibitor concentrations achieved by the DMR process allowed fermentation to ethanol with titers as high as 86 g L-1, which translates into approximately 10.9% v/v ethanol. To our knowledge, this is the first time that titers greater than 10% v/v ethanol in fermentations derived from corn stover without any sugar concentration or purification steps have been reported. As a result, the potential cost savings from high sugar and ethanol titers achieved by the DMR process are also reported using TEA analysis.« less

  20. Twelve years of stover removal increases soil erosion potential without impacting yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) stover (non-grain aboveground biomass) in the U.S. Corn Belt is used increasingly for livestock grazing and co-feed and also is the primary feedstock for cellulosic bioenergy production. Continuous stover removal, however, could alter long-term agricultural productivity by affect...

  1. Cost Effective Bioethanol via Acid Pretreatment of Corn Stover, Saccharification, and Conversion via a Novel Fermentation Organism: Cooperative Research and Development Final Report, CRADA Number: CRD-12-485

    SciTech Connect

    Dowe, N.

    2014-05-01

    This research program will convert acid pretreated corn stover to sugars at the National Renewable Energy Laboratory (NREL) and then transfer these sugars to Honda R&D and its partner the Green Earth Institute (GEI) for conversion to ethanol via a novel fermentation organism. In phase one, NREL will adapt its pretreatment and saccharification process to the unique attributes of this organism, and Honda R&D/GEI will increase the sugar conversion rate as well as the yield and titer of the resulting ethanol. In later phases, NREL, Honda R&D, and GEI will work together at NREL to optimize and scale-up to pilot-scale the Honda R&D/GEI bioethanol production process. The final stage will be to undertake a pilot-scale test at NREL of the optimized bioethanol conversion process.

  2. Corn

    MedlinePlus

    ... composed of a dense core that presses on sensory nerves, causing extreme pain. Soft corns occur between ... a benign condition and may not require medical evaluation. However, if corns become very painful, evaluation should ...

  3. Distribution of structural carbohydrates in corn plants as influenced by corn residue management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As part of the Sun Grant Regional Partnership corn stover project, continuous corn (Zea mays L.) field studies incorporating stover removal management practices (0 and 100% removal) were established in both Alabama and South Carolina. Plots in both states were representative of major soil types in t...

  4. Optimization of enzymatic hydrolysis of steam-exploded corn stover by two approaches: response surface methodology or using cellulase from mixed cultures of Trichoderma reesei RUT-C30 and Aspergillus niger NL02.

    PubMed

    Fang, Hao; Zhao, Chen; Song, Xiang-Yang

    2010-06-01

    To optimize enzymatic hydrolysis of steam-exploded corn stover (SECS), two approaches, response surface methodology (RSM) and utilization of the cellulase from mixed cultures of Trichoderma reesei RUT-C30 and Aspergillus niger NL02, were introduced in this work. The RSM, the first approach, was consisted of Plackett-Burman Design (PBD) and Central Composite Design (CCD). After the optimization of RSM, a model was proposed to predict the optimum value 79.6% confirmed by the experimental result 80.1%. Mixed culture of T. reesei and A. niger was found to be an effective method to enhance cellulolytic enzymes production. Using the cellulase from mixed culture to optimize enzymatic hydrolysis was the second approach. The yield of 85.6% was obtained by the second approach using 25IU/g glucan cellulase. The two approaches were compared and it was found that the second approach was a better one with higher hydrolysis yield and less enzyme dosage. PMID:20149642

  5. Assessing the soil carbon, biomass production, and nitrous oxide emission impact of corn stover management for bioenergy feedstock production using DAYCENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Harvesting crop residue needs to be managed such that agroecosystem health and productivity are protected. DAYCENT, a process-based modeling tool, may be suited to accommodate region-specific factors and provide regional predictions for a broad array of agroecosystem impacts associated with corn sto...

  6. Stover removal effects on seasonal soil water availability under full and deficit irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Removing corn (Zea mays L.) stover for livestock feed or bioenergy feedstock may impact water availability in the soil profile to support crop growth. The role of stover in affecting soil profile water availability will depend on annual rainfall inputs as well as irrigation level. To assess how res...

  7. Short-term stover, tillage, and nitrogen management affect near-surface soil organic matter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) stover removal for biofuel or forage has implications on soil organic C (SOC). The objective of this study was to evaluate short-term (3-yr) stover management (retained or removed [79 removed, across treatments and years]), tillage system (chisel tillage, strip-tillage, and no-til...

  8. Stover harvest – Safe and sustainable with good resource management practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantitative data are needed to guide corn (Zea mays L.) stover harvest for bioenergy production. A 120 acre field study on the Clarion-Nicollet-Webster soil Association near Emmetsburg, IA was established in 2008 to evaluate seven stover management treatments. Each treatment is imposed on three rep...

  9. Nitrogen fertilization affects corn cellulosic biomass and ethanol yields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research results on the effects of N management on corn (Zea mays L.) grain production in high-yielding cropping systems are widely available, but information on its effects on cellulosic ethanol potential from corn stover and cobs is limited. Stover and cob biomass and respective ethanol yields all...

  10. Strategies for Sustainable Corn Stover Feedstock Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Second-generation biofuels will be developed using cellulosic feedstocks rather than grain or oilseed crops that can also be used for food and feed. However, to be sustainable, soil and tillage management strategies used to produce those feedstocks must not irreversibly degrade soil resources. Our o...

  11. Distribution of structural carbohydrates in corn plants across the southeastern USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantifying lignin and carbohydrate composition of corn (Zea mays L.) is important to support the emerging cellulosic biofuels industry. Therefore, field studies with 0 or 100% stover removal were established in Alabama and South Carolina as part of the Sun Grant Regional Partnership Corn Stover Pro...

  12. High dry matter whole-plant corn as a biomass feedstock

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This research investigated the harvest, ambient pre-treatment, and storage of whole-plant corn as an alternative to conventional systems whereby corn grain and stover are fractionated at harvest. Harvesting the whole-plant, both grain and most of the above ground stover, after physiological maturity...

  13. Integrated Corn-Based Bio-Refinery

    SciTech Connect

    2006-04-01

    The Integrated Corn-Based Bio-Refinery (ICBR) process will use new technology to convert corn grain and stover into fermentable sugars for the parallel production of value-added chemicals such as 1,3-propanediol (PDO) and fuel ethanol.

  14. 65. DETAIL OF STOVER WINDMILL REGULATOR (MADE BY STOVER MFG. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    65. DETAIL OF STOVER WINDMILL REGULATOR (MADE BY STOVER MFG. CO., FREEPORT, ILL.) MOUNTED ON STEEL WINDMILL TOWER WITH ELI WINDMILL ON THE GROUND AT STOLL RESIDENCE ABOUT 1-1/2 MILES WEST OF NEBRASKA CITY ON STEAM WAGON ROAD. WINDMILL REGULATORS AUTOMATICALLY TURNED OFF WATER PUMPING WINDMILLS WHEN WATER RESERVOIRS FILLED. INSCRIPTION ON CASTING READS '6-8-9-10 FT. MILLS,' THE SIZES FOR WHICH THIS REGULATOR WAS MADE. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

  15. Response of corn grain, cellulosic biomass, and ethanol yields to nitrogen fertilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) stover will likely play an integral role in near-term attempts to produce renewable cellulosic transportation fuels. However, little is known regarding the influence of nitrogen (N) fertilization on biomass and ethanol yields of stover and cobs. The objectives were to evaluate the...

  16. Environmental Tradeoffs of Stover Removal and Erosion in Indiana

    SciTech Connect

    Alicia English; Wallace E. Tyner; Juan Sesmero; Phillip Owens; David J. Muth, Jr.

    2013-01-01

    When considering the market for biomass from corn stover resources erosion and soil quality issues are important to consider. Removal of stover can be beneficial in some areas, especially when coordinated with other conservation practices, such as vegetative barrier strips and cover crops. However, benefits are highly dependent on several factors, namely if farmers see costs and benefits associated with erosion and the tradeoffs with the removal of biomass. Although typically considered an internal cost, the implication is important to policy and contracting for biomass. This paper uses results from an integrated RUSLE2/WEPS model to incorporate six different regime choices, covering management, harvest and conservation, into a simple profit maximization model to show these tradeoffs explicitly. The results of this work show how different costs for erosion, biomass and conservation managements will affect behavior. If erosion prices are low and no conservation requirement exists, biomass removal will significantly increase erosion, but only in some areas. Alternatively, when erosion prices are high, farmers will parallel socially optimal levels of erosion and conservation management practices can be incentivized through access to a market for stover.

  17. Developing Field Studies to Measure Corn Residue Removal Effects on Soil Organic Matter - A Multi-Location Approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) stover was identified in the Billion Ton Report as a primary feedstock for lignocellulosic biofuel production because it is the most abundant crop residue in the U.S. Potential water and wind erosion effects of stover harvest were considered for those predictions, but several USDA...

  18. Soil greenhouse gas emissions and carbon dynamics of a no-till, corn-based cellulosic ethanol production system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop residues like corn stover perform important functions that promote soil health and provide ecosystem services that influence agricultural sustainability and global biogeochemical cycles. We evaluated the effect of corn residue removal from a no-till, corn-soybean rotation on greenhouse gas (GHG...

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

    NASA Astrophysics Data System (ADS)

    Wilhelm, W. W.; Cushman, J.

    2003-12-01

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

  20. Nitrogen and tillage management affect corn cellulosic yield, composition, and ethanol potential

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) stover and cobs remaining after grain harvest can serve as a feedstock for cellulosic ethanol production. Field trials were conducted at two locations in Minnesota over three years to determine how corn cellulosic yield composition and ethanol yield are influenced by tillage syste...

  1. Nitrogen fertilization effects on irrigated no-till corn production and soil carbon and nitrogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Converting from conventional tillage (CT) to a no-till (NT) production system can affect N requirements for optimizing corn (Zea mays L.) yields while enhancing soil organic carbon (SOC) and N levels. Nitrogen fertilization impacts on irrigated, NT continuous-corn grain, stalk, cob, and stover yiel...

  2. Microbial based pretreatment of corn stover by white rot fungus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pretreatment, as the first step towards conversion of lignocellulosic feedstocks to ethanol, makes up one-third of the total production costs and remains one of the main barriers to commercial success. Typically, harsh methods are used to pretreat lignocellulosic biomass prior to its breakdown to s...

  3. Sustainable corn stover harvest strategies for Midwest agricultural landscapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To support emerging U.S. cellulosic bioenergy industries, 239 site-years of data from field studies at 36 sites in seven states were recently summarized in BioEnergy Research by the ARS Resilient Economic Agricultural Practices (REAP) team [formerly the Renewable Energy Assessment Project (REAP) tea...

  4. Corn Stover Feedstock Trial Update and Future Integrative Visioning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Second-generation biofuels will be developed using cellulosic feedstocks rather than grain or oilseed crops that can also be used for food and feed, but to be sustainable, production of these feedstocks must not degrade soil, water, or air resources. Simulation models can be useful for designing sus...

  5. Corn Stover Feedstock Trials to Support Predictive Modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To be sustainable, feedstock harvest for second-generation biofuels and other bio-products must neither degrade soil, water, or air resources nor negatively impact grain or oilseed crop yields needed to meet food and feed demands. Simulation modeling will help guide the design and development of sus...

  6. CORN FLAVOR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn is a large part of the modern diet through sweeteners, oil, processed foods, and animal-derived foods. In addition, corn is eaten directly in bread and cereal-type foods, snack foods, and foods made from masa flour. Corn gluten meal is a byproduct of grain processed by wet milling. Although pri...

  7. Quantifying Livestock Feed Value of AFEX-Treated DDGS and Subsequent Biorefinery Byproducts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With annual U.S. production of fuel ethanol at nearly 9 billion gallons, coupled with the Renewable Fuels Standard, supplies of coproducts such distillers dried grains with solubles (DDGS) are anticipated to continue to grow for the next several years. DDGS is used as livestock feed. But as suppli...

  8. Ethanol production from enzymatic hydrolysates of AFEX-treated coastal bermudagrass and switchgrass

    SciTech Connect

    Reshamwala, S.; Dale, B.E.; Shawky, B.T.

    1995-12-31

    Switchgrass and coastal bermudagrass were pretreated by ammonia fiber explosion (AFEX), and the treated materials hydrolyzed using 5 IU cellulase/g substrate. Resulting sugar solutions (2-3%, w/v) were fermented with recombinant Klebsiella oxytoca. Glucose was rapidly and completely fermented to ethanol, whereas xylose fermentation was slower and less complete. At higher sugar concentrations ({approximately} 8%) glucose fermentation continued, but xylose fermentation almost ceased. Protein extraction somewhat enhanced ethanol production from coastal bermudagrass. Improved fermentation technologies and media appear necessary for practical mixed-sugar lignocellulosic hydrolyzates.

  9. Tillage and residue management effects on soil carbon and nitrogen under irrigated continuous corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Demand for corn (Zea mays L.) stover as forage or as a cellulosic biofuel has increased the importance of determining the effects of residue removal on biomass production and the soil resource. Objectives were to evaluate grain yield, soil organic carbon (SOC), and total soil N (0 to 150 cm) in a t...

  10. The impact of corn residue removal on soil aggregates and particulate organic matter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Removal of corn stover as a biofuel feedstock is being considered. It is important to understand the implications of this practice when establishing removal guidelines to ensure the long-term sustainability of both the biofuel industry and soil health. Above- and below-ground plant residues are th...

  11. Energy and greenhouse gas profiles of polyhydroxybutyrates derived from corn grain: a life cycle perspective.

    PubMed

    Kim, Seungdo; Dale, Bruce E

    2008-10-15

    Polyhydroxybutyrates (PHB) are well-known biopolymers derived from sugars orvegetable oils. Cradle-to-gate environmental performance of PHB derived from corn grain is evaluated through life cycle assessment (LCA), particularly nonrenewable energy consumption and greenhouse gas emissions. Site-specific process information on the corn wet milling and PHB fermentation and recovery processes was obtained from Telles. Most of energy used in the corn wet milling and PHB fermentation and recovery processes is generated in a cogeneration power plant in which corn stover, assumed to be representative of a variety of biomass sources that could be used, is burned to generate electricity and steam. County level agricultural information is used in estimating the environmental burdens associated with both corn grain and corn stover production. Results show that PHB derived from corn grain offers environmental advantages over petroleum-derived polymers in terms of nonrenewable energy consumption and greenhouse gas emissions. Furthermore, PHB provides greenhouse gas credits, and thus PHB use reduces greenhouse gas emissions compared to petroleum-derived polymers. Corn cultivation is one of the environmentally sensitive areas in the PHB production system. More sustainable practices in corn cultivation (e.g., using no-tillage and winter cover crops) could reduce the environmental impacts of PHB by up to 72%. PMID:18983094

  12. Corn Insect Pests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Historically, the major corn insect pests have been corn rootworms (northern and western), European corn borer, and black cutworm. Bt-corn hybrids are effective against most of these pests. However, Bt-corn hybrids are not effective against corn leaf aphid, corn root aphid, sap beetles, corn rootwor...

  13. Corn transformed

    SciTech Connect

    Moffat, A.S.

    1990-08-10

    Researchers have produced fertile corn transformed with a foreign gene that makes the plants resistant to the herbicide bialaphos. This achievement, is the first report of fertile transgenic corn in the reviewed literature, and it is the capstone of almost a decade's efforts to genetically engineer this country's most important crop. The only other major crop to be so manipulated is rice. The ability produce transgenic corn gives biologists a valuable tool to probe the whys and hows of gene expression and regulation. It may also give plant breeders a way to develop new corn varieties with a speed and predictability that would be impossible with classical breeding techniques.

  14. Corn stover for bioenergy: effect of N fertilization, winter cover crop and stover harvest on vertical biomass distribution and composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biofuel production from plant biomass seems to be a suitable solution to mitigate fossil fuel use and reduce greenhouse gas emissions. Cellulosic biomass seems to be a promising alternative renewable source of energy. The main components of plant material are cellulose, hemicellulose, lignin, ash, p...

  15. Blisters, Calluses, and Corns

    MedlinePlus

    ... Help White House Lunch Recipes Blisters, Calluses, and Corns KidsHealth > For Kids > Blisters, Calluses, and Corns Print ... used to all of that stress. What's a Corn? Like calluses, corns are also areas of hard, ...

  16. Corns and calluses

    MedlinePlus

    Calluses and corns ... Corns and calluses are caused by pressure or friction on skin. A corn is thickened skin on the top or side ... the bunion because it rubs against the shoe. Corns and calluses are not serious problems.

  17. 40 CFR 180.1254 - Aspergillus flavus NRRL 21882; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... NRRL 21882 on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover....

  18. 40 CFR 180.1254 - Aspergillus flavus NRRL 21882; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... NRRL 21882 on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover....

  19. 40 CFR 180.1254 - Aspergillus flavus NRRL 21882; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... NRRL 21882 on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover....

  20. 40 CFR 180.1254 - Aspergillus flavus NRRL 21882; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... NRRL 21882 on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover....

  1. 40 CFR 180.1254 - Aspergillus flavus NRRL 21882; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... NRRL 21882 on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover....

  2. Corn kernel oil and corn fiber oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Unlike most edible plant oils that are obtained directly from oil-rich seeds by either pressing or solvent extraction, corn seeds (kernels) have low levels of oil (4%) and commercial corn oil is obtained from the corn germ (embryo) which is an oil-rich portion of the kernel. Commercial corn oil cou...

  3. Corn-based feedstock for biofuels: Implications for agricultural sustainability

    NASA Astrophysics Data System (ADS)

    Tan, Z.

    2010-12-01

    Crop residue as a source of feedstock for biofuels production must retain ecosystem services and be sustainable. The challenge is to develop cropping system management strategies that balance the demand for increasing biofuel needs with ecosystem sustainability. This study was designed to evaluate impacts of changes in land use and management caused by corn-based biofuel production (grain, cob, stover) on soil fertility and ecosystem sustainability. Our specific goal was to investigate how the levels of corn residue removal influence current soil carbon and nutrient budgets and how these budgets are maintained under proposed production scenarios. Soil organic carbon (SOC), an important carbon component in the life cycle of biofuel production, is a sensitive indicator of cropping system sustainability. We used a soil carbon and nutrient balance approach developed from published field observations and a validated mechanistic model to analyze historical corn grain yields and fertilizer usage associated with various management practices at the county scale across the United States. Our analyses show that ecosystem carbon flux demonstrates significant spatial variability, relying heavily on the total biomass production level and residue harvest intensity; SOC budgets depend mainly on the proportion of residue removal, tillage type, and previous SOC stock level. Our results also indicate that corn cob removal for biofuel has little effect on soil carbon and nutrient balances under conventional management practices, while necessary irrigation can contribute greatly to corn-based biofuel production and ecosystem sustainability in the western side of the Great Plains and the eastern foothills of the Rocky Mountains.

  4. Soil greenhouse gas emissions in response to corn stover removal and tillage management across the US corn belt

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In-field measurements of direct soil greenhouse gas (GHG) emissions provide critical data for quantifying the net energy efficiency and economic feasibility of crop residue-based bioenergy production systems. A major challenge to such assessments has been the paucity of field studies addressing the ...

  5. New perspective on glycoside hydrolase binding to lignin from pretreated corn stover

    DOE PAGESBeta

    Yarbrough, John M.; Mittal, Ashutosh; Mansfield, Elisabeth; Taylor, II, Larry E.; Hobdey, Sarah E.; Sammond, Deanne W.; Bomble, Yannick J.; Crowley, Michael F.; Decker, Stephen R.; Himmel, Michael E.; et al

    2015-12-18

    In this study, non-specific binding of cellulases to lignin has been implicated as a major factor in the loss of cellulase activity during biomass conversion to sugars. It is believed that this binding may strongly impact process economics through loss of enzyme activities during hydrolysis and enzyme recycling scenarios. The current model suggests glycoside hydrolase activities are lost though non-specific/non-productive binding of carbohydrate-binding domains to lignin, limiting catalytic site access to the carbohydrate components of the cell wall.

  6. Biological pretreatment of corn stover with white-rot fungus for improved enzymatic hydrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biological pretreatment of lignocellulosic biomass by white-rot fungus can represent a low-cost and eco-friendly alternative to harsh physical, chemical or physico-chemical pretreatment methods to facilitate enzymatic hydrolysis. However, fungal pretreatment can cause carbohydrate loss and it is, th...

  7. Modeled impacts of cover crops and vegetative barriers on corn stover availability and soil quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Environmentally benign, economically viable, and socially acceptable agronomic strategies are needed to launch a sustainable cellulose-based biofuel industry. Our objective is to demonstrate a landscape planning process that can ensure adequate supplies of lignocellulosic feedstock while protecting ...

  8. Biological pretreatment of corn stover with white-rot fungus for enzymatic hydrolysis and bioethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pretreatment, as the first step towards conversion of lignocellulosic feedstocks to biofuels and/or chemicals remains one of the main barriers to commercial success. Typically, harsh methods are used to pretreat lignocellulosic biomass prior to its breakdown to sugars by enzymes, which also result ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  10. Monitoring Process Streams Towards Understanding Ionic Liquid Pretreatment of Switchgrass and Corn Stover

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pretreatment of Biomass is essential for breaking apart highly ordered and crystalline plant cell walls and loosening the lignin and hemicellulose conjugation to cellulose microfibrils, thereby facilitating enzyme accessibility and adsorption and reducing cotsts of downstream saccharification proces...

  11. Optimizing ethanol and methane production from steam-pretreated, phosphoric acid-impregnated corn stover.

    PubMed

    Bondesson, Pia-Maria; Dupuy, Aurélie; Galbe, Mats; Zacchi, Guido

    2015-02-01

    Pretreatment is of vital importance in the production of ethanol and methane from agricultural residues. In this study, the effects of steam pretreatment with phosphoric acid on enzymatic hydrolysis (EH), simultaneous saccharification and fermentation (SSF), anaerobic digestion (AD) and the total energy output at three different temperatures were investigated. The effect of separating the solids for SSF and the liquid for AD was also studied and compared with using the whole slurry first in SSF and then in AD. Furthermore, the phosphoric acid was compared to previous studies using sulphuric acid or no catalyst. Using phosphoric acid resulted in higher yields than when no catalyst was used. However, compared with sulphuric acid, an improved yield was only seen with phosphoric acid in the case of EH. The higher pretreatment temperatures (200 and 210 °C) resulted in the highest yields after EH and SSF, while the highest methane yield was obtained with the lower pretreatment temperature (190 °C). The highest yield in terms of total energy recovery (78 %) was obtained after pretreatment at 190 °C, but a pretreatment temperature of 200 °C is, however, the best alternative since fewer steps are required (whole slurry in SSF and then in AD) and high product yields were obtained (76 %). PMID:25399069

  12. Xylose production from corn stover biomass by steam explosion combined with enzymatic digestibility.

    PubMed

    Liu, Zhi-Hua; Chen, Hong-Zhang

    2015-10-01

    A novel conversion process using steam explosion combined with enzymatic digestibility was exploited to increase sugar yield. Results showed that glucan and xylan recovery decreased with the increase of holding temperature and residence time in SE, respectively, while glucan and xylan conversion exhibited an opposite trend. The optimal conditions of steam explosion were 160 °C and 48 min, under which glucan and xylan recovery was 93.4% and 71.6%, respectively. Glucan and xylan conversion at 18% solid loading by periodic peristalsis increased by 3.4-5.8% and 4.5-6.2%, respectively, compared with that by water baths shaker. In the whole process, glucose, xylose and total sugar yield reached to 77.3%, 62.8% and 72.3%, respectively. The yield of hydroxymethyl furfural, furfural and lignin-derived products was 6.3 × 10(-2), 7.5 × 10(-2) and less than 3.7 × 10(-2) g/100 g feedstock, respectively. This novel conversion process increased sugar recovery, reduced degradation products formation, improved digestibility efficiency, and hence increased sugar yield. PMID:26143002

  13. Fungal metabolism of fermentation inhibitors present in corn stover dilute acid hydrolysate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Use of agricultural residues for ethanol production requires pretreatment of the material to facilitate release of sugars. Physical-chemical pretreatment of lignocellulosic biomass can, however, give rise to side-products that may be toxic to fermenting microorganisms and hinder utilization of suga...

  14. A simplified method for monomeric carbohydrate analysis of corn stover biomass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Constituent determination of biomass for theoretical ethanol yield (TEY) estimation requires the removal of non-structural carbohydrates prior to analysis to prevent interference with the analytical procedure. According to the accepted U.S. Dept. of Energy-National Renewable Energy Laboratory (NREL)...

  15. Influence of corn residue harvest management on grain, stover, and energy yields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Economic, environmental, and energy independence issues are contributing to rising fossil fuel prices, petroleum supply concerns, and a growing interest in biomass feedstocks as renewable energy sources. Potential feedstocks include perennial grasses, timber, and annual grain crops with our focus be...

  16. Proximate and Ultimate Compositional Changes in Corn Stover during Torrefaction using Thermogravimetric Analyzer and Microwaves

    SciTech Connect

    Jaya Shankar Tumuluru

    2012-07-01

    Abstract The world is currently aiming to reduce the dependence on fossil fuels and to achieve a sustainable renewable supply. Renewable energies represent a diversity of energy sources that can help to maintain the equilibrium of different ecosystems. Among the various sources of renewable energy, biomass is considered carbon neutral because the carbon dioxide released during its use is already part of the carbon cycle. Increasing the use of biomass for energy can help to reduce the negative CO2 impact on the environment and help meet the targets established in the Kyoto Protocol. Energy from biomass can be produced from different processes, including thermochemical (direct combustion, gasification, and pyrolysis), biological (anaerobic digestion, fermentation), or chemical (esterification) technologies. There are lot challenges in using biomass for energy applications. To name few low bulk density, high moisture content, irregular size and shape, hydrophilic nature and low calorific value. In commercial scale operation large quantities of biomass are needed and this will create problems associated with storage and transportation. Furthermore, grinding raw biomass with high moisture content is very challenging as there are no specific equipments and can increase the costs and in some cases it becomes highly impossible. All of these drawbacks led to development of some pretreatment techniques to make biomass more suitable for fuel applications. One of the promising techniques is torrefaction. Torrefaction is heating the biomass in an inert environment or reduced environment. During torrefaction biomass losses moisture, becomes more brittle and with increased energy density values. There are different techniques used for torrefaction of biomass. Fixed bed, bubbling sand bed and moving bed are the most common ones used. The use of microwaves for torrefaction purposes has not been explored. In the present study we looked into the torrefaction of biomass using the regular and microwaves and their effect on proximate and ultimate composition. Studies indicated that microwave torrefaction is a good way to torrefy the biomass in short periods of time. A maximum calorific value of 21 MJ/kg is achievable at 6 min residence time compared to 15 min using the dry torrefaction technique. Increasing the residence time increased the carbon content where a maximum carbon content of 52.20 % was achievable at lower residence time. The loss of volatiles is comparatively lower compared to dry torrefaction technique. Moisture content of microwave torrefied samples was in between 2-2.5 % (w.b).

  17. Biochemical Production of Ethanol from Corn Stover: 2007 State of Technology Model

    SciTech Connect

    Aden, Andy

    2008-05-01

    Since 2001, NREL has kept track of technical research progress in the biochemical process through what are known as “State of Technology” (SOT) assessments. The purpose of this report is to update the FY 2005 SOT model with the latest research results from the past two years.

  18. Synthesis Gas Production by Rapid Solar Thermal Gasification of Corn Stover

    SciTech Connect

    Perkins, C. M.; Woodruff, B.; Andrews, L.; Lichty, P.; Lancaster, B.; Weimer, A. W.; Bingham, C.

    2008-03-01

    Biomass resources hold great promise as renewable fuel sources for the future, and there exists great interest in thermochemical methods of converting these resources into useful fuels. The novel approach taken by the authors uses concentrated solar energy to efficiently achieve temperatures where conversion and selectivity of gasification are high. Use of solar energy removes the need for a combustion fuel and upgrades the heating value of the biomass products. The syngas product of the gasification can be transformed into a variety of fuels useable with today?s infrastructure. Gasification in an aerosol reactor allows for rapid kinetics, allowing efficient utilization of the incident solar radiation and high solar efficiency.

  19. Techno-economic analysis of corn stover fungal fermentation to ethanol

    SciTech Connect

    Meyer, Pimphan; 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 in order 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. Organism performance and technology readiness are split into three groups: near-term (<5 years), mid-term (5-10 years) and long-term (>10 years) process deployment. Processes classified as near-term could reasonably be developed in this shorter time frame, as suggested by recent literature. Mid-term technology process models are based on lab-scale experimental data, and yields near the theoretical limit are used to estimate long-term technology goals. Further research and economic evaluation on the integrated production of chemicals and fuels in biorefineries are recommended.

  20. Techno-economic analysis of corn stover fungal fermentation to ethanol

    SciTech Connect

    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.

  1. Enhancement of xylose utilization from corn stover by a recombinant bacterium for ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recombinant ethanologenic Escherichia coli ferments glucose, xylose and arabinose to ethanol. However, the bacterium preferentially utilizes glucose first, then arabinose and finally xylose (sequential utilization of sugars) during fermentation of lignocellulosic hydrolyzates to ethanol making the p...

  2. Periodic peristalsis releasing constrained water in high solids enzymatic hydrolysis of steam exploded corn stover.

    PubMed

    Liu, Zhi-Hua; Chen, Hong-Zhang

    2016-04-01

    Periodic peristalsis was used to release water constraint and increase high solids enzymatic hydrolysis efficiency. Glucan and xylan conversion in periodic peristalsis enzymatic hydrolysis (PPEH) at 21% solid loading increased by 5.2-6.4% and 6.8-8.8% compared with that in incubator shaker enzymatic hydrolysis (ISEH), respectively. Hydrolysis kinetics suggested that sugars conversion significantly increased within 24h in PPEH compared with ISEH. The peak height of main water pool increased by 7.7-43.1% within 24h in PPEH compared with ISEH. The increases in peak height of main water pool were consistent with the increases in glucan conversion. Submicroscopic particulates and macro granule residues contributed greatly to water constraint compared with glucose, xylose, ethanol, and Tween 80. Smaller particle size and longer residence time resulted in lower water constraint and facilitated the enzymatic hydrolysis performance. Periodic peristalsis was an effective method to reduce water constraint and increase high solids enzymatic hydrolysis efficiency. PMID:26826953

  3. Corn stover harvest increases herbicide movement to subsurface drains – Root Zone Water Quality Model simulations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    BACKGROUND: Removal of crop residues for bioenergy production can alter soil hydrologic properties, but there is little information on its impact on transport of herbicides and their degradation products to subsurface drains. The Root Zone Water Quality Model, previously calibrated using measured fl...

  4. Separation of Lignin from Corn Stover Hydrolysate with Quantitative Recovery of Ionic Liquid

    PubMed Central

    Underkofler, Kaylee A.; Teixeira, Rodrigo E.; Pietsch, Stephen A.; Knapp, Kurtis G.; Raines, Ronald T.

    2015-01-01

    Abundant lignocellulosic biomass could become a source of sugars and lignin, potential feedstocks for the now emergent bio-renewable economy. The production and conversion of sugars from biomass have been well-studied, but far less is known about the production of lignin that is amenable to valorization. Here we report the isolation of lignin generated from the hydrolysis of biomass dissolved in the ionic liquid 1-butyl-3-methylimidazolium chloride. We show that lignin can be isolated from the hydrolysate slurry by simple filtration or centrifugation, and that the ionic liquid can be recovered quantitatively by a straightforward wash with water. The isolated lignin is not only free from ionic liquid, but also lacks cellulosic residues and is substantially depolymerized, making it a promising feedstock for valorization by conversion into fuels and chemicals. PMID:25866701

  5. Biological pretreatment of corn stover by Phlebia brevispora for enhanced enzymatic hydrolysis and efficient ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pretreatment, as the first step towards conversion of lignocellulosic feedstocks to ethanol remains one of the main barriers to commercial success. Typically, harsh methods are used to pretreat lignocellulosic biomass prior to its breakdown to sugars by enzymes, which also result in fermentation in...

  6. Delaying corn rootworm resistance to Bt corn.

    PubMed

    Tabashnik, Bruce E; Gould, Fred

    2012-06-01

    Transgenic crops producing Bacillus thuringiensis (Bt) toxins for insect control have been successful, but their efficacy is reduced when pests evolve resistance. To delay pest resistance to Bt crops, the U.S. Environmental Protection Agency (EPA) has required refuges of host plants that do not produce Bt toxins to promote survival of susceptible pests. Such refuges are expected to be most effective if the Bt plants deliver a dose of toxin high enough to kill nearly all hybrid progeny produced by matings between resistant and susceptible pests. In 2003, the EPA first registered corn, Zea mays L., producing a Bt toxin (Cry3Bb1) that kills western corn rootworm, Diabrotica virgifera virgifera LeConte, one of the most economically important crop pests in the United States. The EPA requires minimum refuges of 20% for Cry3Bb1 corn and 5% for corn producing two Bt toxins active against corn rootworms. We conclude that the current refuge requirements are not adequate, because Bt corn hybrids active against corn rootworms do not meet the high-dose standard, and western corn rootworm has rapidly evolved resistance to Cry3Bb1 corn in the laboratory, greenhouse, and field. Accordingly, we recommend increasing the minimum refuge for Bt corn targeting corn rootworms to 50% for plants producing one toxin active against these pests and to 20% for plants producing two toxins active against these pests. Increasing the minimum refuge percentage can help to delay pest resistance, encourage integrated pest management, and promote more sustainable crop protection. PMID:22812111

  7. Quantitative Trait Loci and Trait Correlations for Maize Stover Cell Wall Composition and Glucose Release for Cellulosic Ethanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In cellulosic ethanol production, the efficiency of converting maize (Zea mays L.) stover into fermentable sugars partly depends on the stover cell wall structure. Breeding for improved stover quality for cellulosic ethanol may benefit from the use of molecular markers. However, limited quantitative...

  8. Our Mother Corn.

    ERIC Educational Resources Information Center

    Mathers, Sherry; And Others

    Developed to provide an understanding of the magnitude of the role of corn, referred to as Mother Corn in the cultures of the Seneca, Pawnee, and Hopi tribes, the student text provides information on the tribes' basic lifestyles and the way they grew and used corn in three different parts of the United States. The section on the origin of corn…

  9. Corn rootworms and Bt resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn rootworms have been a major pest of corn for many years. As their name suggests, corn rootworms damage corn plants by feeding on the roots. Western and northern corn rootworms have overcome practices farmers use to keep their population numbers down, such as insecticides and crop rotation. Cor...

  10. Identifying resistance in corn to southwestern corn borer, fall armyworm, and corn earworm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Southwestern corn borer, Diatraea grandiosella Dyar; fall armyworm, Spodoptera frugiperda (J.E. Smith); and corn earworm, Helicoverpa zea Boddie, are major insect pests of corn, Zea mays L., in the southern United States. Corn germplasm with resistance to leaf feeding by southwestern corn borer a...

  11. Carbon Corn: Development of a sustainable agroecosystem

    NASA Astrophysics Data System (ADS)

    Wacha, K. M.; Papanicolaou, T.

    2009-12-01

    Corn is a valuable commodity to our society that not only provides a vital food source, but can increase the sustainability of our agroecosystem. This includes ethanol/biodiesel production through biomass collection of stover and residue, monitoring storage of carbon in the soil for commodity exchange, and decreasing the erosion-induced spread of pollutants by increasing organic matter content in the soil. In our study, the CENTURY5 model was used to simulate a wide range of crop rotations and tillage practices at the Clear Creek watershed located in South Amana, Iowa. In addition, sediment budget data were created from the Watershed Erosion Prediction Project (WEPP) model based on simulations ran for the same watershed. The numerical field experiments were conducted within the watershed in constructed corn plots that mimicked common farm practices. This included row spacing, seed planting depth, fertilizer applications of nitrogen, phosphorus and potash, and tillage. Data recorded during the experimental time-line included canopy height, vegetation cover, temperature, residue and soil moisture content. Base measurements of organic material levels and the pH of the soil were also taken. Present work consists of conducting rainfall experiments at the plot-scale using the Norton Ladder Rainfall Simulator and analyzing how changes in the soil micro-topography and residue cover affect the re-distribution of the organic carbon in the soil. Micro-topography will be obtained by scanning the bed surface with a state-of-the-art laser system with a spatial resolution of 0.5 mm. Erosion amounts and residue estimations will be verified with CENTURY5 and WEPP models. Results from this study will advance our knowledge in sustainable agroecosystems at the plot scale and allow us to scale up to watershed levels, providing estimations of carbon storage, biomass production, and erosion at a larger global stage.

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

    SciTech Connect

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

    2002-06-01

    The U.S. Department of Energy (DOE) is promoting the development of ethanol from lignocellulosic feedstocks as an alternative to conventional petroleum-based transportation fuels. DOE funds both fundamental and applied research in this area and needs a method for predicting cost benefits of many research proposals. To that end, the National Renewable Energy Laboratory (NREL) has modeled many potential process designs and estimated the economics of each process during the last 20 years. This report is an update of the ongoing process design and economic analyses at NREL.

  13. Corn blight watch experiment

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The corn blight problem is briefly described how the experiment was organized and conducted, the effect of the blight on the 1971 crop, and some conclusions that may be drawn as a result of the experiment. The information is based on preliminary reports of the Corn Blight Watch Steering Committee and incorporates much illustrative material conceived at Purdue University.

  14. PRODUCING HIGH CORN YIELDS.

    ERIC Educational Resources Information Center

    Illinois Univ., Urbana. Coll. of Agriculture.

    RESOURCE MATERIAL ON CORN PRODUCTION FOR HIGH SCHOOL VOCATIONAL AGRICULTURE AND ADULT FARMER CLASSES WAS DESIGNED BY A STATE LEVEL GROUP OF SUBJECT MATTER SPECIALISTS, TEACHER EDUCATORS, SUPERVISORS, AND TEACHERS TO HELP SOLVE PROBLEMS THAT CONFRONT CORN PRODUCERS AT PLANTING TIME. THE SUBJECT MATTER CONCERNS PLANTING TIME, DEPTH, ROW WIDTH,…

  15. Effect of feeding sweet sorghum stover-based complete rations on the growth performance and carcass characteristics of ram lambs.

    PubMed

    Babu, Jagannatham; Kumari, Nagireddy Nalini; Reddy, Yerradoddi Ramana; Raghunandan, Thirunahari; Sridhar, Kalakuntla

    2015-03-01

    The present study was carried out to evaluate the effect of sweet sorghum stover (cost $0.05/kg) supplementation as complete balanced diet (at 60 % level) on sheep performance, carcass characteristics and economics in comparison to maize stover (cost $0.08/kg) and sorghum stover (cost $0.09/kg) (conventional roughage sources). Eighteen Nellore ram lambs aged about 3 months (average body weight 15.65 ± 0.10 kg) were randomly allotted to three complete diets formulated with roughage to concentrate ratio of 60:40 (on dry matter basis) using sorghum stover (SS), maize stover (MS) and sweet sorghum stover (SSS) as roughage sources for a period of 120 days. The average daily dry matter intake (g/kg w(0.75)), average daily gain (grams) and feed conversion efficiency were similar among the experimental diets. No significant differences were observed among the treatment groups for the mean live weight (kg) at slaughter, empty body weight (kg) dressing percentage on live weight basis or on empty body weight basis, proportion of different wholesale cuts, percentage of edible offals and non-edible offals, proportion of meat, meat/bone ratio and chemical composition of meat. Thus, it can be concluded that sweet sorghum stover can be incorporated in the complete diets of lambs by replacing conventional roughages such as sorghum stover and maize stover processed as mash form without affecting the performance, nutrient digestibility and carcass characteristics. PMID:25627816

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

    PubMed Central

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Wang, Michael; Han, Jeongwoo; Dunn, Jennifer B.; Cai, Hao; Elgowainy, Amgad

    2012-12-01

    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.

  18. Kepler Corn Maze

    NASA Video Gallery

    The Dell'Osso Family Farm, located on the outskirts of Lathrop, California held the grand opening of their corn maze that was designed with a NASA theme. The maze is part of a nation-wide group of ...

  19. TQM at Corning.

    PubMed

    Houghton, J

    1992-01-01

    Houghton has been with Corning for 30 years, up through the ranks. Now, as chairman and CEO, his individual leadership stamp is TQM. It's a major turn-around story with Total Quality at its center. PMID:10117839

  20. Argentina corn yield model

    NASA Technical Reports Server (NTRS)

    Callis, S. L.; Sakamoto, C.

    1984-01-01

    A model based on multiple regression was developed to estimate corn yields for the country of Argentina. A meteorological data set was obtained for the country by averaging data for stations within the corn-growing area. Predictor variables for the model were derived from monthly total precipitation, average monthly mean temperature, and average monthly maximum temperature. A trend variable was included for the years 1965 to 1980 since an increasing trend in yields due to technology was observed between these years.

  1. 21 CFR 184.1321 - Corn gluten.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... glutelin. Corn gluten is a byproduct of the wet milling of corn for starch. The gluten fraction is washed... conversion of the starch in whole or various fractions of dry milled corn to corn syrups. (b) The...

  2. 21 CFR 184.1321 - Corn gluten.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... glutelin. Corn gluten is a byproduct of the wet milling of corn for starch. The gluten fraction is washed... conversion of the starch in whole or various fractions of dry milled corn to corn syrups. (b) The...

  3. 21 CFR 184.1321 - Corn gluten.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... glutelin. Corn gluten is a byproduct of the wet milling of corn for starch. The gluten fraction is washed... conversion of the starch in whole or various fractions of dry milled corn to corn syrups. (b) The...

  4. 21 CFR 184.1321 - Corn gluten.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... glutelin. Corn gluten is a byproduct of the wet milling of corn for starch. The gluten fraction is washed... conversion of the starch in whole or various fractions of dry milled corn to corn syrups. (b) The...

  5. Enzymatic conversion of pretreated biomass into fermentable sugars for biorefinery operation

    NASA Astrophysics Data System (ADS)

    Gao, Dahai

    2011-12-01

    Depleting petroleum reserves and potential climate change caused by fossil fuel consumption have attracted significant attention towards the use of alternative renewable resources for production of fuels and chemicals. Lignocellulosic biomass provides a plentiful resource for the sustainable production of biofuels and biochemicals and could serve as an important contributor to the world energy portfolio in the near future. Successful biological conversion of lignocellulosic biomass requires an efficient and economical pretreatment method, high glucose/xylose yields during enzymatic hydrolysis and fermentation of both hexose and pentose to ethanol. High enzyme loading is a major economic bottleneck for the commercial processing of pretreated lignocellulosic biomass to produce fermentable sugars. Optimizing the enzyme cocktail for specific types of pretreated biomass allows for a significant reduction in enzyme loading without sacrificing hydrolysis yield. Core glycosyl hydrolases were isolated and purified from various sources to help rationally optimize an enzyme cocktail to digest ammonia fiber expansion (AFEX) treated corn stover. The four core cellulases were endoglucanase I (EG I), cellobiohydrolase I (CBH I), cellobiohydrolase II (CBH II) and beta-Glucosidase (betaG). The two core hemicellulases were an endoxylanase (EX) and a beta-xylosidase (betaX). A diverse set of accessory hemicellulases from bacterial sources was found necessary to enhance the synergistic action of cellulases hydrolysing AFEX pretreated corn stover. High glucose (around 80%) and xylose (around 70%) yields were achieved with a moderate enzyme loading (˜20 mg protein/g glucan) using an in-house developed enzyme cocktail and this cocktail was compared to commercial enzyme. Studying the binding properties of cellulases to lignocellulosic substrates is critical to achieving a fundamental understanding of plant cell wall saccharification. Lignin auto-fluorescence and degradation products

  6. Rapid quantification of major reaction products formed during thermochemical pretreatment of lignocellulosic biomass using GC-MS.

    PubMed

    Humpula, James F; Chundawat, Shishir P S; Vismeh, Ramin; Jones, A Daniel; Balan, Venkatesh; Dale, Bruce E

    2011-04-15

    Accurate quantification of reaction products formed during thermochemical pretreatment of lignocellulosic biomass would lead to a better understanding of plant cell wall deconstruction for production of cellulosic biofuels and biochemicals. However, quantification of some process byproducts, most notably acetamide, acetic acid and furfural, present several analytical challenges using conventional liquid chromatography methods. Therefore, we have developed a high-throughput gas chromatography based mass spectrometric (GC-MS) method in order to quantify relevant compounds without requiring time-consuming sample derivatization prior to analysis. Solvent extracts of untreated, ammonia fiber expansion (AFEX) treated and dilute-acid treated corn stover were analyzed by this method. Biomass samples were extracted with acetone using an automated solvent extractor, serially diluted and directly analyzed using the proposed GC-MS method. Acetone was the only solvent amongst water, methanol and acetonitrile that did not contain detectable background levels of the target compounds or facilitate a buildup of plant-derived residues in the GC injector, which decreased analytical reproducibility. Quantitative results were based on the method of standard addition and external standard calibration curves. PMID:21444255

  7. Indiana Corn Dry Mill

    SciTech Connect

    2006-09-01

    The goal of this project is to perform engineering, project design, and permitting for the creation and commercial demonstration of a corn dry mill biorefinery that will produce fuel-grade ethanol, distillers dry grain for animal feed, and carbon dioxide for industrial use.

  8. Foliar diseases of corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf blights and spots caused by fungi are some of the most destructive diseases of corn in the US and around the world. Correct identification of the disease is very important in determining the best means of control. For example, gray leaf spot of maize can be caused by one of at least two species...

  9. Maize stover and cob cell wall composition and ethanol potential as affected by nitrogen fertilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize (Zea mays L.) stover and cobs are potential feedstock sources for cellulosic ethanol production. Nitrogen (N) fertilization is an important management decision that influences cellulosic biomass and grain production, but its effect on cell wall composition and subsequent cellulosic ethanol pro...

  10. Mechanisms of antimony adsorption onto soybean stover-derived biochar in aqueous solutions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Limited mechanistic knowledge is available to understand how biochar interacts with trace elements that exist predominantly as oxoanions, such as antimony (Sb). Soybean stover biochars were produced at 300 degrees C (SBC300) and 700 degrees C (SBC700), and were characterized by BET, Boehm titration,...

  11. Digestibility and performance of steers fed low-quality crop residues treated with calcium oxide to partially replace corn in distillers grains finishing diets.

    PubMed

    Shreck, A L; Nuttelman, B L; Harding, J L; Griffin, W A; Erickson, G E; Klopfenstein, T J; Cecava, M J

    2015-02-01

    Two studies were conducted to identify methods for treating crop residues to improve digestibility and value in finishing diets based on corn grain and corn wet distillers grain with solubles (WDGS). In Exp. 1, 336 yearling steers (initial BW 356 ± 11.5 kg) were used in a 2 × 3 + 1 factorial arrangement of treatments with 6 pens per treatment. Factors were 3 crop residues (corn cobs, wheat straw, and corn stover) and 2 treatments where crop residues were either fed (20% diet DM) in their native form (NT) or alkaline treated with 5% CaO (DM basis) and hydrated to 50% DM before anaerobic storage (AT). Intakes were not affected by diet (F test; P = 0.30). An interaction between chemical treatment and residue (P < 0.01) was noted for final BW, ADG, G:F, and HCW. Greater final BW was observed for treated stover (4.6%) and straw (5.6%) compared with NT residues; however, AT and NT cobs were similar. Treated straw (9.7%) and stover (12.5%) resulted in greater ADG (P < 0.01) and improved G:F (10.7% and 5.0%, respectively; P < 0.01) compared with NT forms. In Exp. 2, ruminally fistulated steers (n = 5) were used in an unbalanced 5 × 7 incomplete Latin square design with a 2 × 3 + 1 factorial arrangement of treatments. Factors were crop residue (corn cobs, wheat straw, and corn stover) and chemical treatment (NT or AT) fed at 25% of diet DM. Greater DM (73.7% vs. 66.1%; P < 0.01), OM (77.0% vs. 68.5%; P < 0.01), fat (89.2 vs. 85.2; P = 0.02), and NDF (66.8% vs. 51.5%; P < 0.01) digestibilities were noted for AT than for NT. However, no difference (P > 0.10) was observed between control (46% corn; DM basis) and AT (31% corn; DM basis) for DM digestibility (70.7% vs. 73.7%) or OM digestibility (72.1% vs. 77.0%). Dry matter intakes were not different between treated and untreated diets (P = 0.38), but lower (P < 0.01) NDF intake was observed for treated diets (3.1 vs. 3.5 kg/d), suggesting that CaO treatment was effective in solubilizing some carbohydrate. These data

  12. Comparison of corn stover cell wall polysaccharide degradability by rumen microbes and a cellulosic ethanol conversion process

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Release of fermentable cell wall sugars in the cellulosic ethanol conversion process is assumed similar to rumen degradability; however, available literature has only reported surrogate rumen degradation measures (dry matter, neutral detergent fiber, and fermentation gases). We determined 72-h in vi...

  13. Comparison of TLUD and atmospherically-controlled retort methods of preparing biochar using corn stover and wheat straw feedstocks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar is a very versatile and useful material in many applications beyond carbon sequestration in soils. Rubber composite filler, sorptive media for toxic or other undesirable species in water, and peat moss replacement are just three examples of biochar applications we have studied at our laborat...

  14. Acceleration of the Enzymatic Hydrolysis of Corn Stover and Sugar Cane Bagasse Celluloses by Low Intensity Uniform Ultrasound

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The cost-competitive production of bio-ethanol and other biofuels is currently impeded, mostly by high cost and low efficiency of enzymatic hydrolysis of feedstock biomass and especially plant celluloses. Despite substantial reduction in the cost of production of cellulolytic enzymes in recent times...

  15. Conversion of residual organics in corn stover-derived biorefinery stream to bioenergy via microbial fuel cell

    SciTech Connect

    Borole, Abhijeet P; Hamilton, Choo Yieng; Schell, Daniel J

    2012-01-01

    A biorefinery process typically uses about 4-10 times as much water as the amount of biofuel generated. The wastewater produced in a biorefinery process contains residual sugars, 5-furfural, phenolics, and other pretreatment and fermentation byproducts. Treatment of the wastewater can reduce the need for fresh water and potentially add to the environmental benefits of the process. Use of microbial fuel cells (MFCs) for conversion of the various organics present in a post-fermentation biorefinery stream is reported here. The organic loading was varied over a wide range to assess removal efficiency, coulombic efficiency and power production. A coulombic efficiency of 40% was observed for a low loading of 1% (0.66 g/L) and decreased to 1.8% for the undiluted process stream (66.4 g/L organic loading). A maximum power density of 1180 mW/m2 was observed at a loading of 8%. Excessive loading was found to result in poor electrogenic performance. The results indicate that operation of an MFC at an intermediate loading using dilution and recirculation of the process stream can enable effective treatment with bioenergy recovery.

  16. An economic comparison of different fermentation configurations to convert corn stover to ethanol using Z. mobilis and Saccharomyces.

    PubMed

    Dutta, Abhijit; Dowe, Nancy; Ibsen, Kelly N; Schell, Daniel J; Aden, Andy

    2010-01-01

    Numerous routes are being explored to lower the cost of cellulosic ethanol production and enable large-scale production. One critical area is the development of robust cofermentative organisms to convert the multiple, mixed sugars found in biomass feedstocks to ethanol at high yields and titers without the need for processing to remove inhibitors. Until such microorganisms are commercialized, the challenge is to design processes that exploit the current microorganisms' strengths. This study explored various process configurations tailored to take advantage of the specific capabilities of three microorganisms, Z. mobilis 8b, S. cerevisiae, and S. pastorianus. A technoeconomic study, based on bench-scale experimental data generated by integrated process testing, was completed to understand the resulting costs of the different process configurations. The configurations included whole slurry fermentation with a coculture, and separate cellulose simultaneous saccharification and fermentation (SSF) and xylose fermentations with none, some or all of the water to the SSF replaced with the fermented liquor from the xylose fermentation. The difference between the highest and lowest ethanol cost for the different experimental process configurations studied was $0.27 per gallon ethanol. Separate fermentation of solid and liquor streams with recycle of fermented liquor to dilute the solids gave the lowest ethanol cost, primarily because this option achieved the highest concentrations of ethanol after fermentation. Further studies, using methods similar to ones employed here, can help understand and improve the performance and hence the economics of integrated processes involving enzymes and fermentative microorganisms. PMID:19785041

  17. Simplifying pyrolysis; using gasification to produce corn stover and wheat straw biochar for sorptive and horitcultural media

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar is a renewable, useful material that can be utilized in many different applications. Biochar is commonly produced via pyrolysis methods using a retort-style oven with inert gas. Gasification is another method that can utilize pyrolysis to produce biochar, but with the advantage of not requir...

  18. Environmental Enhancement Through Corn Stover Utilization: Cooperative Research and Development Final Report, CRADA Number CRD-06-00174

    SciTech Connect

    Czernik, S.

    2010-08-01

    We have developed a rapid bio-oil analysis protocol based on the application of mass spectrometry, infra-red spectrometry, and multivariate statistical analysis. This protocol was successfully applied to characterize bio-oil samples from the Iowa State University (ISU) fast pyrolysis unit and to relate those characteristics to the feedstock and the process conditions.

  19. Lower-cost cellulosic ethanol production from corn stover using ß-glucosidase producing yeast Clavispora NRRL Y-50464

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For cellulosic ethanol production, decomposition of cellulosic polymers and enzymatic hydrolysis and saccharification are necessary for microbes to efficiently utilize the biomass harbored sugars. The need of additional enzymes and processing steps increase cost of biofuels. To reduce the cost of ce...

  20. 21 CFR 184.1262 - Corn silk and corn silk extract.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Corn silk and corn silk extract. 184.1262 Section... Affirmed as GRAS § 184.1262 Corn silk and corn silk extract. (a) Corn silk is the fresh styles and stigmas of Zea mays L. collected when the corn is in milk. The filaments are extracted with dilute ethanol...

  1. Size reduction of high- and low-moisture corn stalks by linear knife grid system

    SciTech Connect

    Womac, A.R.; Igathinathane, C.; Sokhansanj, Shahabaddine; Narayan, S.

    2009-04-01

    High- and low-moisture corn stalks were tested using a linear knife grid size reduction device developed for first-stage size reduction. The device was used in conjunction with a universal test machine that quantified shearing stress and energy characteristics for forcing a bed of corn stalks through a grid of sharp knives. No published engineering performance data for corn stover with similar devices are available to optimize performance; however, commercial knife grid systems exist for forage size reduction. From the force displacement data, mean and maximum ultimate shear stresses, cumulative and peak mass-based cutting energies for corn stalks, and mean new surface area-based cutting energies were determined from 4 5 refill runs at two moisture contents (78.8% and 11.3% wet basis), three knife grid spacings (25.4, 50.8, and 101.6 mm), and three bed depths (50.8, 101.6, and 152.4 mm). In general, the results indicated that peak failure load, ultimate shear stress, and cutting energy values varied directly with bed depth and inversely with knife grid spacing. Mean separation analysis established that high- and low-moisture conditions and bed depths 101.6 mm did not differ significantly (P < 0.05) for ultimate stress and cutting energy values, but knife grid spacing were significantly different. Linear knife grid cutting energy requirements for both moisture conditions of corn stalks were much smaller than reported cutting energy requirements. Ultimate shear stress and cutting energy results of this research should aid the engineering design of commercial scale linear knife gird size reduction equipment for various biomass feedstocks.

  2. Insecticidal proteins from Bacillus thuringiensis protect corn from corn rootworms.

    PubMed

    Moellenbeck, D J; Peters, M L; Bing, J W; Rouse, J R; Higgins, L S; Sims, L; Nevshemal, T; Marshall, L; Ellis, R T; Bystrak, P G; Lang, B A; Stewart, J L; Kouba, K; Sondag, V; Gustafson, V; Nour, K; Xu, D; Swenson, J; Zhang, J; Czapla, T; Schwab, G; Jayne, S; Stockhoff, B A; Narva, K; Schnepf, H E; Stelman, S J; Poutre, C; Koziel, M; Duck, N

    2001-07-01

    Field tests of corn co-expressing two new delta-endotoxins from Bacillus thuringiensis (Bt) have demonstrated protection from root damage by western corn rootworm (Diabrotica virgifera virgifera LeConte). The level of protection exceeds that provided by chemical insecticides. In the bacterium, these proteins form crystals during the sporulation phase of the growth cycle, are encoded by a single operon, and have molecular masses of 14 kDa and 44 kDa. Corn rootworm larvae fed on corn roots expressing the proteins showed histopathological symptoms in the midgut epithelium. PMID:11433280

  3. Callosities, corns, and calluses.

    PubMed Central

    Singh, D.; Bentley, G.; Trevino, S. G.

    1996-01-01

    Inappropriate shoes, abnormal foot mechanics, and high levels of activity produce pressure and friction that lead to corns and calluses. Most lesions can be managed conservatively by proper footwear, orthoses, and, if necessary, regular paring. The lesions usually disappear when the causative mechanical forces are removed. Surgery is rarely indicated and should be specifically aimed at correcting the abnormal mechanical stresses. Images Fig 2 Fig 3 Fig 4 Fig 6 Fig 7 PMID:8646101

  4. Rumen degradability characteristics of normal maize stover and silage, and quality protein maize silage-based diets offered to cows.

    PubMed

    Tamir, Berhan; Gebrehawariat, Ephrem; Tegegne, Azage; Kortu, Mohammed Y

    2012-10-01

    Rumen degradability characteristics of dry matter (DM), organic matter (OM) and crude protein (CP) of normal maize (NM) stover (T1)-, NM silage (T2)- and quality protein maize (QPM) silage (T3)-based diets were studied using three rumen-fistulated Boran × Friesian non-lactating cows (371 ± 32.00 kg) in 3 × 3 Latin Square Design. Cows were supplemented with a similar concentrate mix. In sacco degradability of DM and OM indicated that the (a) values of DM (128) and OM (114) for NM stover were lower (P < 0.001) than that for NM silage (268 and 253) and for QPM silage (323 and 303), respectively. The (a) value for CP was lower (P < 0.05) for QPM silage (286) than for NM stover (404) and NM silage (326). The (b) values of DM in NM stover (597) and NM silage (535) were higher (P < 0.05) than in QPM silage (499). The (b) value of CP in NM stover (372) was lower (P < 0.05) than in NM silage (655) and in QPM silage (608). Rate of degradation of OM in NM stover and NM silage, each with 0.03, was faster (P < 0.01) than in QPM silage (0.02). Moreover, QPM silage had higher potentially degradable fraction for DM (821) (P < 0.05) and OM (840) (P < 0.01) than DM (725) and OM (712) in NM stover. The mean rumen ammonia concentration (209 mg/l) of QPM silage was higher (P < 0.05) than that of NM stover (179 mg/l) and NM silage (170 mg/l). The average rumen pH (6.1) in cows fed QPM silage was lowest (P < 0.05) compared to pH (6.3) in cows fed either NM stover or silage. The concentration of total volatile fatty acids (116 mmol/l) in the rumen of cows incubated with QPM silage was higher (P < 0.001) than in those incubated with NM stover (113 mmol/l) and NM silage (110 mmol/l). It was concluded that QPM silage-based diet was superior in DM and OM degradability, and had higher ammonia and VFA concentration than NM stover-based diet. No differences have been observed in all parameters measured between QPM and NM silages. PMID:22366928

  5. 40 CFR 180.1219 - Foramsulfuron; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... pesticide foramsulfuron is exempted from the requirement of a tolerance in corn, field, grain/corn, field, forage/ corn, field, stover/corn, pop, grain/corn, pop, forage/corn, pop, stover; corn, sweet, forage; corn, sweet, kernel plus cob with husks removed; corn, sweet, stover when applied as a herbicide...

  6. 40 CFR 180.1219 - Foramsulfuron; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... pesticide foramsulfuron is exempted from the requirement of a tolerance in corn, field, grain/corn, field, forage/ corn, field, stover/corn, pop, grain/corn, pop, forage/corn, pop, stover; corn, sweet, forage; corn, sweet, kernel plus cob with husks removed; corn, sweet, stover when applied as a herbicide...

  7. 40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... tolerance is established for residues of Aspergillus flavus AF36 in or on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover,...

  8. 40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... tolerance is established for residues of Aspergillus flavus AF36 in or on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover,...

  9. 40 CFR 180.1219 - Foramsulfuron; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... pesticide foramsulfuron is exempted from the requirement of a tolerance in corn, field, grain/corn, field, forage/ corn, field, stover/corn, pop, grain/corn, pop, forage/corn, pop, stover; corn, sweet, forage; corn, sweet, kernel plus cob with husks removed; corn, sweet, stover when applied as a herbicide...

  10. 40 CFR 180.1219 - Foramsulfuron; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... pesticide foramsulfuron is exempted from the requirement of a tolerance in corn, field, grain/corn, field, forage/ corn, field, stover/corn, pop, grain/corn, pop, forage/corn, pop, stover; corn, sweet, forage; corn, sweet, kernel plus cob with husks removed; corn, sweet, stover when applied as a herbicide...

  11. 40 CFR 180.1219 - Foramsulfuron; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... pesticide foramsulfuron is exempted from the requirement of a tolerance in corn, field, grain/corn, field, forage/ corn, field, stover/corn, pop, grain/corn, pop, forage/corn, pop, stover; corn, sweet, forage; corn, sweet, kernel plus cob with husks removed; corn, sweet, stover when applied as a herbicide...

  12. 40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... tolerance is established for residues of Aspergillus flavus AF36 in or on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover,...

  13. 21 CFR 184.1321 - Corn gluten.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... principal protein component of corn endosperm. It consists mainly of zein and glutelin. Corn gluten is a... soluble proteins. Corn gluten is also produced as a byproduct during the conversion of the starch in...

  14. Earthworms modify microbial community structure and accelerate maize stover decomposition during vermicomposting.

    PubMed

    Chen, Yuxiang; Zhang, Yufen; Zhang, Quanguo; Xu, Lixin; Li, Ran; Luo, Xiaopei; Zhang, Xin; Tong, Jin

    2015-11-01

    In the present study, maize stover was vermicomposted with the epigeic earthworm Eisenia fetida. The results showed that, during vermicomposting process, the earthworms promoted decomposition of maize stover. Analysis of microbial communities of the vermicompost by high-throughput pyrosequencing showed more complex bacterial community structure in the substrate treated by the earthworms than that in the control group. The dominant microbial genera in the treatment with the earthworms were Pseudoxanthomonas, Pseudomonas, Arthrobacter, Streptomyces, Cryptococcus, Guehomyces, and Mucor. Compared to the control group, the relative abundance of lignocellulose degradation microorganisms increased. The results indicated that the earthworms modified the structure of microbial communities during vermicomposting process, activated the growth of lignocellulose degradation microorganisms, and triggered the lignocellulose decomposition. PMID:26139410

  15. SCREENING FOR SUGAR AND ETHANOL PROCESSING CHARACTERISTICS FROM ANATOMICAL FRACTIONS OF WHEAT STOVER

    SciTech Connect

    K. B. Duguid; M. D. Montross; C. W. Radtke; C. L. Crofcheck; S. A. Shearer; R. L. Hoskinson

    2007-08-01

    Due to concerns with stover collection systems, soil sustainability, and processing costs to ethanol, there are opportunities to investigate the optimal plant fractions to collect. Wheat stover fractions were separated by hand and analyzed for glucan, xylan, acid soluble lignin, acid insoluble lignin, and ash composition. Internodes had the highest glucan content (38.2% dry basis) and the other fractions varied between 29.9 and 33.4%. The stover fractions were pretreated with either 0, 0.4, or 0.8% NaOH for 2 hrs at room temperature, washed, autoclaved, and saccharified. In addition, acid pretreated samples underwent simultaneous saccharification and fermentation (SSF) to ethanol. In general, the acid and alkaline pretreatments produced similar trends with leaves requiring very little pretreatment to achieve high conversion rates (greater than 80%). Chaff responded very well to pretreatment and high conversion efficiencies resulted when pretreated under alkaline or acidic conditions. Nodes and internodes were more recalcitrant than the other anatomical fractions. Pretreatment with 0.8% sulfuric acid (0.24 g sulfuric acid/g biomass) did not result in a significantly higher conversion of glucan to ethanol as the native material. Pretreatment with 0.8% NaOH (0.06 g NaOH/g biomass) at room temperature for 2 hrs resulted in high conversion efficiencies for all plant fractions, greater than 73% of the available glucan. These differences in pretreatment susceptibilities suggest that a biomass collection system that removes specific portions of wheat stover could result in significant differences in ethanol production costs

  16. Economic Assessment of Supercritical CO2 Extraction of Waxes as Part of a Maize Stover Biorefinery

    PubMed Central

    Attard, Thomas M.; McElroy, Con Robert; Hunt, Andrew J.

    2015-01-01

    To date limited work has focused on assessing the economic viability of scCO2 extraction to obtain waxes as part of a biorefinery. This work estimates the economic costs for wax extraction from maize stover. The cost of manufacture (COM) for maize stover wax extraction was found to be €88.89 per kg of wax, with the fixed capital investment (FCI) and utility costs (CUT) contributing significantly to the COM. However, this value is based solely on scCO2 extraction of waxes and does not take into account the downstream processing of the biomass following extraction. The cost of extracting wax from maize stover can be reduced by utilizing pelletized leaves and combusting the residual biomass to generate electricity. This would lead to an overall cost of €10.87 per kg of wax (based on 27% combustion efficiency for electricity generation) and €4.56 per kg of wax (based on 43% combustion efficiency for electricity generation). A sensitivity analysis study showed that utility costs (cost of electricity) had the greatest effect on the COM. PMID:26263976

  17. Economic Assessment of Supercritical CO2 Extraction of Waxes as Part of a Maize Stover Biorefinery.

    PubMed

    Attard, Thomas M; McElroy, Con Robert; Hunt, Andrew J

    2015-01-01

    To date limited work has focused on assessing the economic viability of scCO2 extraction to obtain waxes as part of a biorefinery. This work estimates the economic costs for wax extraction from maize stover. The cost of manufacture (COM) for maize stover wax extraction was found to be € 88.89 per kg of wax, with the fixed capital investment (FCI) and utility costs (CUT) contributing significantly to the COM. However, this value is based solely on scCO2 extraction of waxes and does not take into account the downstream processing of the biomass following extraction. The cost of extracting wax from maize stover can be reduced by utilizing pelletized leaves and combusting the residual biomass to generate electricity. This would lead to an overall cost of € 10.87 per kg of wax (based on 27% combustion efficiency for electricity generation) and €4.56 per kg of wax (based on 43% combustion efficiency for electricity generation). A sensitivity analysis study showed that utility costs (cost of electricity) had the greatest effect on the COM. PMID:26263976

  18. Management of corn leafhopper (Homoptera: Cicadellidae) and corn stunt disease in sweet corn using reflective mulch.

    PubMed

    Summers, C G; Stapleton, J J

    2002-04-01

    Plastic reflective mulches significantly reduced populations of corn leafhopper, Dalbulus maidis (DeLong & Wolcott), adults and the incidence of corn stunt disease caused by Spiroplasma kunkelii (CSS) in late planted sweet corn (Zea mays L.). The reflective mulches were more effective than were either foliar or soil applied insecticides in managing both the leafhopper and the pathogen it transmits. Yields of marketable ears were 1.5 to 2 times greater in reflective mulch plots than from fallow plots. This was due to larger ears (individual ear weight and length) rather than an increase in the number of ears. The use of reflective mulches provides an alternative strategy to insecticides in the management of both D. maidis and corn stunt disease. Such a strategy may prove useful to growers in Latin America and to limited resource growers and organic growers in the United States who wish to grow corn without the use of insecticides. PMID:12020008

  19. Aflatoxin in corn hybrids infested at different growth stages with southwestern corn borer (Lepidoptera: Crambidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxin is a potent toxin produced by the fungus Aspergillus flavus. Contamination of corn, Zea mays L., with aflatoxin greatly reduces the value of corn grain and is a major impediment to profitable corn production in the South. Infestation of developing corn ears with southwestern corn borer, D...

  20. Screening for corn rootworm (Coleoptera: Chrysomelidae) resistance to transgenic Bt corn in North Dakota

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Western (WCR), Diabrotica virgifera virgifera LeConte, and northern corn rootworms (NCR), D. barberi Smith & Lawrence, are major economic pests of corn in much of the U.S. Corn Belt. Western corn rootworm resistance to transgenic corn expressing Bt (Bacillus thuringiensis) endotoxins has been confi...

  1. 9 CFR 319.102 - Corned beef round and other corned beef cuts.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... beef cuts. 319.102 Section 319.102 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE... Meats, Unsmoked and Smoked § 319.102 Corned beef round and other corned beef cuts. In preparing “Corned Beef Round” and other corned beef cuts, except “Corned Beef Briskets,” the curing solution shall...

  2. 9 CFR 319.102 - Corned beef round and other corned beef cuts.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... beef cuts. 319.102 Section 319.102 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE... Meats, Unsmoked and Smoked § 319.102 Corned beef round and other corned beef cuts. In preparing “Corned Beef Round” and other corned beef cuts, except “Corned Beef Briskets,” the curing solution shall...

  3. 40 CFR 180.440 - Tefluthrin; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... commodities: Commodity Parts per million Corn, field, forage 0.06 Corn, field, grain 0.06 Corn, field, stover 0.06 Corn, pop, grain 0.06 Corn, pop, stover 0.06 Corn, sweet, forage 0.06 Corn, sweet, kernel plus cob with husks removed 0.06 Corn, sweet, stover 0.06 (b) Section 18 emergency exemptions....

  4. 40 CFR 180.486 - Phosphorothioic acid, 0,0-diethyl 0-(1,2,2,2-tetrachloroethyl) ester; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the following raw agricultural commodities: Commodity Parts per million Corn, field, forage 0.01 Corn, field, grain 0.01 Corn, field, stover 0.01 Corn, pop, grain 0.01 Corn, pop, stover 0.01 Corn, sweet, forage 0.01 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 0.01...

  5. 40 CFR 180.440 - Tefluthrin; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... commodities: Commodity Parts per million Corn, field, forage 0.06 Corn, field, grain 0.06 Corn, field, stover 0.06 Corn, pop, grain 0.06 Corn, pop, stover 0.06 Corn, sweet, forage 0.06 Corn, sweet, kernel plus cob with husks removed 0.06 Corn, sweet, stover 0.06 (b) Section 18 emergency exemptions....

  6. 40 CFR 180.440 - Tefluthrin; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... commodities: Commodity Parts per million Corn, field, forage 0.06 Corn, field, grain 0.06 Corn, field, stover 0.06 Corn, pop, grain 0.06 Corn, pop, stover 0.06 Corn, sweet, forage 0.06 Corn, sweet, kernel plus cob with husks removed 0.06 Corn, sweet, stover 0.06 (b) Section 18 emergency exemptions....

  7. 40 CFR 180.440 - Tefluthrin; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... commodities: Commodity Parts per million Corn, field, forage 0.06 Corn, field, grain 0.06 Corn, field, stover 0.06 Corn, pop, grain 0.06 Corn, pop, stover 0.06 Corn, sweet, forage 0.06 Corn, sweet, kernel plus cob with husks removed 0.06 Corn, sweet, stover 0.06 (b) Section 18 emergency exemptions....

  8. 40 CFR 180.440 - Tefluthrin; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... commodities: Commodity Parts per million Corn, field, forage 0.06 Corn, field, grain 0.06 Corn, field, stover 0.06 Corn, pop, grain 0.06 Corn, pop, stover 0.06 Corn, sweet, forage 0.06 Corn, sweet, kernel plus cob with husks removed 0.06 Corn, sweet, stover 0.06 (b) Section 18 emergency exemptions....

  9. 75 FR 80489 - Notice of Receipt of Several Pesticide Petitions Filed for Residues of Pesticide Chemicals in or...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-22

    ...- (CAS Reg. No. 37764-25-3) in or on corn, field, forage; corn, field, grain; corn, field, stover; corn, pop, grain; corn, pop, stover; corn, sweet, forage; corn, sweet, kernel plus cob with husks removed; and corn, sweet, stover at 0.05 parts per million (ppm). Dichlormid (R-25788) is an herbicide...

  10. Characterization and Functionality of Corn Germ Proteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to evaluate the functional properties of protein extracted from wet-milled corn germ and identify potential applications of the recovered protein. Corn germ comprises 12% of the total weight of normal dent corn and about 29% of the corn protein (moisture-free and oil- free ...

  11. Diapause in northern corn rootworm (Coleoptera: Chrysomelidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diabroticite corn rootworms are prominent pests of maize and have adapted to both cultural and chemical management methods. In response to a widely used corn-soybean crop rotation in the U.S. Corn Belt over several years, northern corn rootworm (NCR) populations adapted by increasing the proportion ...

  12. 21 CFR 184.1865 - Corn syrup.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Corn syrup. 184.1865 Section 184.1865 Food and....1865 Corn syrup. (a) Corn syrup, commonly called “glucose sirup” or “glucose syrup,” is obtained by... dehydrated form (dried glucose sirup). Depending on the degree of hydrolysis, corn syrup may contain,...

  13. Corn Culture: A Story of Intelligent Design

    ERIC Educational Resources Information Center

    Todd, Jude

    2008-01-01

    Scientists are not sure of how corn was created. There were two competing genetic theories about how corn came to be. One theory maintains that corn had been teased out of a wheatlike grass called teosinte (genus Zea), and the other contends that one now-extinct ancestor of corn had crossed with another grass, "Tripsacum," several millennia ago.…

  14. Characterization of Corn Grains for Ethanol Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objectives of this study were to understand how the composition of corn kernels and starch structure affect enzyme hydrolysis of starch in dry-grind corn and ethanol yield from yeast fermentation. Four selected corn inbred lines were used in this study. Starch in uncooked dry-grind corn samples sh...

  15. Effects of Pyramided Bt Corn and Blended Refuges on Western Corn Rootworm and Northern Corn Rootworm (Coleoptera: Chrysomelidae).

    PubMed

    Keweshan, Ryan S; Head, Graham P; Gassmann, Aaron J

    2015-04-01

    The western corn rootworm, Diabrotica virgifera virgifera LeConte, and the northern corn rootworm, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae), are major pests of corn (Zea mays L). Several transgenic corn events producing insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) kill corn rootworm larvae and reduce injury to corn roots. However, planting of Bt corn imposes selection on rootworm populations to evolve Bt resistance. The refuge strategy and pyramiding of multiple Bt toxins can delay resistance to Bt crops. In this study, we assessed the impact of four treatments--1) non-Bt corn, 2) Cry3Bb1 corn, 3) corn pyramided with Cry3Bb1 and Cry34/35Ab1, and 4) pyramided corn with a blended refuge--on survival, time of adult emergence, and size of western and northern corn rootworm. All treatments with Bt corn led to significant reductions in the number of adults that emerged per plot. However, at one location, we identified Cry3Bb1-resistant western corn rootworm. In some cases Bt treatments reduced size of adults and delayed time of adult emergence, with effects most pronounced for pyramided corn. For both species, the number of adults that emerged from pyramided corn with a blended refuge was significantly lower than expected, based solely on emergence from pure stands of pyramided corn and non-Bt corn. The results of this study indicate that pyramided corn with a blended refuge substantially reduces survival of both western and northern corn rootworm, and as such, should be a useful tool within the context of a broader integrated pest management strategy. PMID:26470183

  16. Ethanol extraction of phytosterols from corn fiber

    DOEpatents

    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.

  17. Diagravitropism in corn roots

    NASA Technical Reports Server (NTRS)

    Leopold, A. C.; Wettlaufer, S. H.

    1988-01-01

    The diagravitropic behavior of Merit corn (Zea mays L.) roots grown in darkness provides an opportunity for comparison of two qualitatively different gravitropic systems. As with positive gravitropism, diagravitropism is shown to require the presence of the root cap, have a similar time course for the onset of curvature, and a similar presentation time. In contrast with positive gravitropism, diagravitropism appears to have a more limited requirement for calcium, for it is insensitive to the elution of calcium by EGTA and insensitive to the subsequent addition of a calcium/EGTA complex. These results are interpreted as indicating that whereas the same sensing system is shared by the two types of gravitropism, separate transductive systems are involved, one for diagravitropism, which is relatively independent of calcium, and one for positive gravitropism, which is markedly dependent on calcium.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    average sugarcane ethanol system producing ethanol and electricity can save about 13 Mg CO2eq/ha of land compared to 12 in the early 2000s, while a recent average corn ethanol system saves about 6.2 Mg CO2eq/ha compared to near zero GHG savings in the early 2000s. The net energy balance (i.e., energy produced minus energy consumed) per ha for a recent average sugarcane ethanol system producing both ethanol and electricity is about 160 GJ/ha compared to 140 GJ/ha in early 2000s, while the recent average corn ethanol system achieves a net energy production of about 90 GJ/ha compares to only 30 GJ/ha in the early 2000s. The land use efficiency of corn and sugarcane ethanol systems, especially future systems, can vary depending on factors such as the assumed technologies, the suite of co-products produced, field practices, and technological learning. For example, projected future (2020) advanced sugarcane ethanol systems could save 22 Mg CO2eq/ha while an advanced corn ethanol system using integrated gasification of corn stover for electricity production could save 9.3Mg CO2eq/ha. Future advanced sugarcane ethanol systems could produce 210 GJ of net energy/ha while an advanced corn ethanol system using integrated gasification of corn stover for electricity production could achieve 110 GJ/ha.

  19. Comparison of the Carbon Budget, Evapotranspiration, and Albedo Effect between the Biofuel Crops Switchgrass and Corn

    NASA Astrophysics Data System (ADS)

    Eichelmann, E.; Wagner-Riddle, C.; Warland, J. S.; Deen, B.; Voroney, P.

    2015-12-01

    Switching from annual cropping systems to perennial crops like switchgrass (Panicum virgatum L.) for biofuel feedstock production will have implications on carbon and water cycling as well as biophysical parameters, such as surface albedo.We conducted eddy covariance measurements of carbon dioxide and water fluxes over a mature (>5 years) switchgrass field over three years (2012 to 2014) and a continuous corn field during the year 2014. Both fields were located in Southern Ontario, Canada. Results for carbon and water cycling were compared between the two crops for the year 2014. Differences in surface albedo between the two biofuel cropping systems were compared for the years 2012, 2013, and 2014. In 2014 switchgrass was a carbon sink with a net ecosystem carbon balance (NECB) of -66±59 g C m-2, while corn was a carbon source with an NECB of 328±30 g C m-2 for a scenario where corn grain only is harvested and 634±34 g C m-2 for a scenario where both grain and stover are harvested. Annual evapotranspiration in 2014 was higher for the corn field (608.7±12 mm) than for the switchgrass field (517.0±8 mm). Albedo measurements showed an average annual negative radiative forcing effect for the switchgrass field compared to corn. Differences in albedo were largest in spring and fall when radiative forcing values of -10.2 and -5.5 W m-2 were observed, respectively.Comparing carbon cycling results from previous years, the switchgrass field was a source of carbon in 2012 (NEBC 106±45 g C m-2), but a small sink of carbon in 2013 (NEBC -59±45) and 2014. On average over the three measurement years, the switchgrass field was carbon neutral.Qualitative analysis of the carbon budget, evapotranspiration, and albedo results from this study suggest that biofuel produced from switchgrass can have more climate benefits than biofuel from continuous corn. This study provides important data for improvement of Life Cycle Analysis of switchgrass biofuel.

  20. 21 CFR 155.131 - Canned field corn.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Canned field corn. 155.131 Section 155.131 Food... Canned field corn. (a) Identity. (1) Canned field corn conforms to the definition and standard of... corn by § 155.130(a), except that the corn ingredient consists of succulent field corn or a mixture...

  1. 21 CFR 155.131 - Canned field corn.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Canned field corn. 155.131 Section 155.131 Food... Canned field corn. (a) Identity. (1) Canned field corn conforms to the definition and standard of... corn by § 155.130(a), except that the corn ingredient consists of succulent field corn or a mixture...

  2. 21 CFR 155.131 - Canned field corn.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Canned field corn. 155.131 Section 155.131 Food... Canned field corn. (a) Identity. (1) Canned field corn conforms to the definition and standard of... corn by § 155.130(a), except that the corn ingredient consists of succulent field corn or a mixture...

  3. 21 CFR 155.131 - Canned field corn.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Canned field corn. 155.131 Section 155.131 Food... Canned field corn. (a) Identity. (1) Canned field corn conforms to the definition and standard of... corn by § 155.130(a), except that the corn ingredient consists of succulent field corn or a mixture...

  4. 21 CFR 155.131 - Canned field corn.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Canned field corn. 155.131 Section 155.131 Food... Canned field corn. (a) Identity. (1) Canned field corn conforms to the definition and standard of... corn by § 155.130(a), except that the corn ingredient consists of succulent field corn or a mixture...

  5. Field-based assessment of resistance to Bt Corn by Western Corn Rootworm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Western corn rootworm, Diabrotica virgifera virgifera LeConte, is a serious pest of corn and is managed with Bt corn that produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt). Beginning in 2009, severe injury to Bt corn producing Cry3Bb1 was observed in some cornfields ...

  6. Utilisation of Corn (Zea mays) Bran and Corn Fiber in the Production of Food Components

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the past decade, the demand for ethanol has increased dramatically. Demand for other products of corn milling, such as starches and sweeteners, is also expected to increase. With the increase in demand for industrial and food use of corn, the production of byproducts, such as corn fiber, corn...

  7. 77 FR 10617 - Wellsboro & Corning Railroad, LLC-Acquisition and Operation Exemption-Wellsboro & Corning...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-22

    ... Surface Transportation Board Wellsboro & Corning Railroad, LLC--Acquisition and Operation Exemption--Wellsboro & Corning Railroad Company Wellsboro & Corning Railroad, LLC (WCLLC), a noncarrier, has filed a verified notice of exemption under 49 CFR 1150.31 to acquire from Wellsboro & Corning Railroad Company...

  8. Resistance to Bt corn by western corn rootworm (Coleoptera: Chrysomelidae) in the U.S. corn belt

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgenic Bt corn hybrids that produce insecticidal proteins from the bacterium Bacillus thuringiensis Berliner have become the standard insect management tactic across the United States Corn Belt. Widespread planting of Bt corn creates intense selection pressure for target insects to develop resis...

  9. Mechanisms of antimony adsorption onto soybean stover-derived biochar in aqueous solutions.

    PubMed

    Vithanage, Meththika; Rajapaksha, Anushka Upamali; Ahmad, Mahtab; Uchimiya, Minori; Dou, Xiaomin; Alessi, Daniel S; Ok, Yong Sik

    2015-03-15

    Limited mechanistic knowledge is available on the interaction of biochar with trace elements (Sb and As) that exist predominantly as oxoanions. Soybean stover biochars were produced at 300 °C (SBC300) and 700 °C (SBC700), and characterized by BET, Boehm titration, FT-IR, NMR and Raman spectroscopy. Bound protons were quantified by potentiometric titration, and two acidic sites were used to model biochar by the surface complexation modeling based on Boehm titration and NMR observations. The zero point of charge was observed at pH 7.20 and 7.75 for SBC300 and SBC700, respectively. Neither antimonate (Sb(V)) nor antimonite (Sb(III)) showed ionic strength dependency (0.1, 0.01 and 0.001 M NaNO3), indicating inner sphere complexation. Greater adsorption of Sb(III) and Sb(V) was observed for SBC300 having higher -OH content than SBC700. Sb(III) removal (85%) was greater than Sb(V) removal (68%). Maximum adsorption density for Sb(III) was calculated as 1.88 × 10(-6) mol m(-2). The Triple Layer Model (TLM) successfully described surface complexation of Sb onto soybean stover-derived biochar at pH 4-9, and suggested the formation of monodentate mononuclear and binuclear complexes. Spectroscopic investigations by Raman, FT-IR and XPS further confirmed strong chemisorptive binding of Sb to biochar surfaces. PMID:25602696

  10. Corn-in-chip: Mesofluidic Device for Corn Root

    NASA Astrophysics Data System (ADS)

    Kreis, Kevin; Ryu, Sangjin

    2015-03-01

    Plants have a collection of beneficial microorganisms in a region surrounding their roots called the rhizosphere. Although rhizosphere management could increase crop yield, little is known about the interaction between plant roots and their associated microorganisms. Thus we aim to simulate the rhizosphere and monitor root-microbe interactions in the lab environment, and have chosen corn as a model plant because of its economic significance. Here we present our preliminary study to develop a transparent mesofluidic device accommodating the root of corn seedlings into its channel and allowing further growth of the root.

  11. The 1971 corn blight watch experiment

    NASA Technical Reports Server (NTRS)

    Clifton, J. W.

    1972-01-01

    The successful fulfillment of the objectives for the 1971 corn blight watch experiment is reported. The objectives were: (1) detect the development and spread of corn blight during the growing season across the Corn Belt; (2) assess different levels of infection in the Corn Belt; (3) amplify data acquired by ground observations to better appraise current blight status and the probable impact on crop production; and (4) estimate through extrapolation the applicability of these techniques to similar situations occurring in the future.

  12. 21 CFR 184.1865 - Corn syrup.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Corn syrup. 184.1865 Section 184.1865 Food and... Substances Affirmed as GRAS § 184.1865 Corn syrup. (a) Corn syrup, commonly called “glucose sirup” or “glucose syrup,” is obtained by partial hydrolysis of corn starch with safe and suitable acids or...

  13. 21 CFR 184.1865 - Corn syrup.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Corn syrup. 184.1865 Section 184.1865 Food and... Substances Affirmed as GRAS § 184.1865 Corn syrup. (a) Corn syrup, commonly called “glucose sirup” or “glucose syrup,” is obtained by partial hydrolysis of corn starch with safe and suitable acids or...

  14. "King Corn": Teaching the Food Crisis

    ERIC Educational Resources Information Center

    Swinehart, Tim

    2012-01-01

    "King Corn" is in so many ways the story of how government food policy has entirely remade the food landscape in the United States over the last 40 years. From the massive expansion of the number of acres of corn grown across the country, to the ever-increasing ways that corn is incorporated into the food production process, to the industrial…

  15. 9 CFR 319.100 - Corned beef.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... permitting that use in this subchapter or 9 CFR Chapter III, Subchapter E, or in 21 CFR Chapter I, Subchapter... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Corned beef. 319.100 Section 319.100... Corned beef. “Corned Beef” shall be prepared from beef briskets, navels, clods, middle ribs,...

  16. Geographic information systems in corn rootworm management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn rootworms (Diabrotica spp. Coleoptera: Chrysomelidae) are serious pests of corn (Zea mays) in the United States and Europe. Control measures for corn rootworms (CRW) were historically based upon chemical pesticides and crop rotation. Pesticide use created environmental and economic concerns. In...

  17. Does Bt Corn Really Produce Tougher Residues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bt corn hybrids produce insecticidal proteins that are derived from a bacterium, Bacillus thuringiensis. There have been concerns that Bt corn hybrids produce residues that are relatively resistant to decomposition. We conducted four experiments that examined the decomposition of corn residues und...

  18. 21 CFR 184.1865 - Corn syrup.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Substances Affirmed as GRAS § 184.1865 Corn syrup. (a) Corn syrup, commonly called “glucose sirup” or “glucose syrup,” is obtained by partial hydrolysis of corn starch with safe and suitable acids or enzymes. It may also occur in the dehydrated form (dried glucose sirup). Depending on the degree of...

  19. 21 CFR 184.1865 - Corn syrup.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Substances Affirmed as GRAS § 184.1865 Corn syrup. (a) Corn syrup, commonly called “glucose sirup” or “glucose syrup,” is obtained by partial hydrolysis of corn starch with safe and suitable acids or enzymes. It may also occur in the dehydrated form (dried glucose sirup). Depending on the degree of...

  20. Alfalfa: A Companion Crop with Corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn grain-based ethanol is the major form of biofuel production in the USA. Corn is an attractive biofuel crop because it is easy to manage, process, and ship; is high yielding; and has significant industry support and research. However, there are concerns about growing corn in rotation with soyb...