Effects of dilute-acid pretreatment conditions on filtration performance of corn stover hydrolyzate

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

Sievers, David A.; Kuhn, Erik M.; Tucker, Melvin P.

In this study, the reaction conditions used during dilute-acid pretreatment of lignocellulosic biomass control the carbohydrate digestion yield and also hydrolyzate properties. Depending on the conversion route of interest, solid-liquid separation (SLS) may be required to split the hemicellulose-rich liquor from the cellulose-rich insoluble solids, and slurry properties are important for SLS. Corn stover was pretreated at different reaction conditions and the slurries were assessed for conversion yield and filtration performance. Increasing pretreatment temperature reduced the solids mean particle size and resulted in slower slurry filtration rates when vacuum filtered or pressure filtered. Corn stover pretreated at 165 °C formore » 10 min and with 1% H 2SO 4 exhibited the highest xylose yield and best filtration performance with a no-wash filtration rate of 80 kg/h m 2 and cake permeability of 15 x 10 -15.« less

Effects of dilute-acid pretreatment conditions on filtration performance of corn stover hydrolyzate

DOE PAGES

Sievers, David A.; Kuhn, Erik M.; Tucker, Melvin P.; ...

2017-06-28

In this study, the reaction conditions used during dilute-acid pretreatment of lignocellulosic biomass control the carbohydrate digestion yield and also hydrolyzate properties. Depending on the conversion route of interest, solid-liquid separation (SLS) may be required to split the hemicellulose-rich liquor from the cellulose-rich insoluble solids, and slurry properties are important for SLS. Corn stover was pretreated at different reaction conditions and the slurries were assessed for conversion yield and filtration performance. Increasing pretreatment temperature reduced the solids mean particle size and resulted in slower slurry filtration rates when vacuum filtered or pressure filtered. Corn stover pretreated at 165 °C formore » 10 min and with 1% H 2SO 4 exhibited the highest xylose yield and best filtration performance with a no-wash filtration rate of 80 kg/h m 2 and cake permeability of 15 x 10 -15.« less

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

USDA-ARS?s Scientific Manuscript database

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 ...

Biological pretreatment of corn stover with Phlebia brevispora NRRL-13108 for enhanced enzymatic hydrolysis and efficient ethanol production

USDA-ARS?s Scientific Manuscript database

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. In this work, solid state cultivation of corn stover with Phlebia bre...

Alkaline organosolv pretreatment of corn stover for enhancing the enzymatic digestibility.

PubMed

Yuan, Wei; Gong, Zhiwei; Wang, Guanghui; Zhou, Wenting; Liu, Yi; Wang, Xuemin; Zhao, Mi

2018-06-14

In the present study, a sodium hydroxide-methanol solution (SMs) pretreatment of corn stover was described to overcome biomass recalcitrance for the first time. Effects of sodium hydroxide loading, solid-to-liquid ratio, processing time and temperature on enzymatic saccharification were studied in detail. The SMs pretreatment could significantly enhance the enzyme accessibility of corn stover, minimize the degradation of sugar polymers, and decrease the energy consumption. 97.5% glucan and 83.5% xylan were preserved in the regenerated corn stover under the optimal condition. Subsequent enzymatic digestibilities of glucan and xylan reached 97.2% and 80.3%, respectively. The enzyme susceptibility of the regenerated samples was explained by their physical and chemical characteristics. This strategy provides a promising alternative for better techno-economic of the lignocelluloses-to-sugars routes. Copyright © 2018 Elsevier Ltd. All rights reserved.

Pipeline transport and simultaneous saccharification of corn stover.

PubMed

Kumar, Amit; Cameron, Jay B; Flynn, Peter C

2005-05-01

Pipeline transport of corn stover delivered by truck from the field is evaluated against a range of truck transport costs. Corn stover transported by pipeline at 20% solids concentration (wet basis) or higher could directly enter an ethanol fermentation plant, and hence the investment in the pipeline inlet end processing facilities displaces comparable investment in the plant. At 20% solids, pipeline transport of corn stover costs less than trucking at capacities in excess of 1.4 M drytonnes/yr when compared to a mid range of truck transport cost (excluding any credit for economies of scale achieved in the ethanol fermentation plant from larger scale due to multiple pipelines). Pipelining of corn stover gives the opportunity to conduct simultaneous transport and saccharification (STS). If current enzymes are used, this would require elevated temperature. Heating of the slurry for STS, which in a fermentation plant is achieved from waste heat, is a significant cost element (more than 5 cents/l of ethanol) if done at the pipeline inlet unless waste heat is available, for example from an electric power plant located adjacent to the pipeline inlet. Heat loss in a 1.26 m pipeline carrying 2 M drytonnes/yr is about 5 degrees C at a distance of 400 km in typical prairie clay soils, and would not likely require insulation; smaller pipelines or different soil conditions might require insulation for STS. Saccharification in the pipeline would reduce the need for investment in the fermentation plant, saving about 0.2 cents/l of ethanol. Transport of corn stover in multiple pipelines offers the opportunity to develop a large ethanol fermentation plant, avoiding some of the diseconomies of scale that arise from smaller plants whose capacities are limited by issues of truck congestion.

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.

Ammonia pretreatment of corn stover enables facile lignin extraction

DOE PAGES

Mittal, Ashutosh; Katahira, Rui; Donohoe, Bryon S.; ...

2017-02-09

Thermochemical pretreatment of lignocellulose is often employed to render polysaccharides more digestible by carbohydrate-active enzymes to maximize sugar yields. The fate of lignin during pretreatment, however, is highly dependent on the chemistry employed and must be considered in cases where lignin valorization is targeted alongside sugar conversion—an important feature of future biorefinery development. Here, a two-step process is demonstrated in which anhydrous ammonia (AA) pretreatment is followed by mild NaOH extraction on corn stover to solubilize and fractionate lignin. As known, AA pretreatment simultaneously alters the structure of cellulose with enhanced digestibility while redistributing lignin. The AA-pretreated residue is thenmore » extracted with dilute NaOH at mild conditions to maximize lignin separation, resulting in a digestible carbohydrate-rich solid fraction and a solubilized lignin stream. Lignin removal of more than 65% with over 84% carbohydrate retention is achieved after mild NaOH extraction of AA-pretreated corn stover with 0.1 M NaOH at 25 °C. Two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy of the AA-pretreated residue shows that ammonolysis of ester bonds occurs to partially liberate hydroxycinnamic acids, and the AA-pretreated/NaOH-extracted residue exhibits a global reduction of all lignin moieties caused by reduced lignin content. A significant reduction (~70%) in the weight-average molecular weight ( M w) of extracted lignin is also achieved. Imaging of AA-pretreated/NaOH extracted residues show extensive delamination and disappearance of coalesced lignin globules from within the secondary cell walls. Glycome profiling analyses demonstrates ultrastructural level cell wall modifications induced by AA pretreatment and NaOH extraction, resulting in enhanced extractability of hemicellulosic glycans, indicating enhanced polysaccharide accessibility. The glucose and xylose yields from enzymatic hydrolysis of AA-pretreated/NaOH-extracted corn stover were higher by ~80% and ~60%, respectively, compared to untreated corn stover at 1% solids loadings. For digestions at 20% solids, a benefit of NaOH extraction is realized in achieving ~150 g/L of total monomeric sugars (glucose, xylose, and arabinose) in the enzymatic hydrolysates from AA-pretreated/NaOH-extracted corn stover. Altogether, this process enables facile lignin extraction in tandem with a leading thermochemical pretreatment approach, demonstrating excellent retention of highly digestible polysaccharides in the solid phase and a highly depolymerized, soluble lignin-rich stream.« less

Ammonia pretreatment of corn stover enables facile lignin extraction

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

Mittal, Ashutosh; Katahira, Rui; Donohoe, Bryon S.

Thermochemical pretreatment of lignocellulose is often employed to render polysaccharides more digestible by carbohydrate-active enzymes to maximize sugar yields. The fate of lignin during pretreatment, however, is highly dependent on the chemistry employed and must be considered in cases where lignin valorization is targeted alongside sugar conversion—an important feature of future biorefinery development. Here, a two-step process is demonstrated in which anhydrous ammonia (AA) pretreatment is followed by mild NaOH extraction on corn stover to solubilize and fractionate lignin. As known, AA pretreatment simultaneously alters the structure of cellulose with enhanced digestibility while redistributing lignin. The AA-pretreated residue is thenmore » extracted with dilute NaOH at mild conditions to maximize lignin separation, resulting in a digestible carbohydrate-rich solid fraction and a solubilized lignin stream. Lignin removal of more than 65% with over 84% carbohydrate retention is achieved after mild NaOH extraction of AA-pretreated corn stover with 0.1 M NaOH at 25 °C. Two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy of the AA-pretreated residue shows that ammonolysis of ester bonds occurs to partially liberate hydroxycinnamic acids, and the AA-pretreated/NaOH-extracted residue exhibits a global reduction of all lignin moieties caused by reduced lignin content. A significant reduction (~70%) in the weight-average molecular weight ( M w) of extracted lignin is also achieved. Imaging of AA-pretreated/NaOH extracted residues show extensive delamination and disappearance of coalesced lignin globules from within the secondary cell walls. Glycome profiling analyses demonstrates ultrastructural level cell wall modifications induced by AA pretreatment and NaOH extraction, resulting in enhanced extractability of hemicellulosic glycans, indicating enhanced polysaccharide accessibility. The glucose and xylose yields from enzymatic hydrolysis of AA-pretreated/NaOH-extracted corn stover were higher by ~80% and ~60%, respectively, compared to untreated corn stover at 1% solids loadings. For digestions at 20% solids, a benefit of NaOH extraction is realized in achieving ~150 g/L of total monomeric sugars (glucose, xylose, and arabinose) in the enzymatic hydrolysates from AA-pretreated/NaOH-extracted corn stover. Altogether, this process enables facile lignin extraction in tandem with a leading thermochemical pretreatment approach, demonstrating excellent retention of highly digestible polysaccharides in the solid phase and a highly depolymerized, soluble lignin-rich stream.« less

Compatibility of High-Moisture Storage for Biochemical Conversion of Corn Stover: Storage Performance at Laboratory and Field Scales.

PubMed

Wendt, Lynn M; Murphy, J Austin; Smith, William A; Robb, Thomas; Reed, David W; Ray, Allison E; Liang, Ling; He, Qian; Sun, Ning; Hoover, Amber N; Nguyen, Quang A

2018-01-01

Wet anaerobic storage of corn stover can provide a year-round supply of feedstock to biorefineries meanwhile serving an active management approach to reduce the risks associated with fire loss and microbial degradation. Wet logistics systems employ particle size reduction early in the supply chain through field-chopping which removes the dependency on drying corn stover prior to baling, expands the harvest window, and diminishes the biorefinery size reduction requirements. Over two harvest years, in-field forage chopping was capable of reducing over 60% of the corn stover to a particle size of 6 mm or less. Aerobic and anaerobic storage methods were evaluated for wet corn stover in 100 L laboratory reactors. Of the methods evaluated, traditional ensiling resulted in <6% total solid dry matter loss (DML), about five times less than the aerobic storage process and slightly less than half that of the anaerobic modified-Ritter pile method. To further demonstrate the effectiveness of the anaerobic storage, a field demonstration was completed with 272 dry tonnes of corn stover; DML averaged <5% after 6 months. Assessment of sugar release as a result of dilute acid or dilute alkaline pretreatment and subsequent enzymatic hydrolysis suggested that when anaerobic conditions were maintained in storage, sugar release was either similar to or greater than as-harvested material depending on the pretreatment chemistry used. This study demonstrates that wet logistics systems offer practical benefits for commercial corn stover supply, including particle size reduction during harvest, stability in storage, and compatibility with biochemical conversion of carbohydrates for biofuel production. Evaluation of the operational efficiencies and costs is suggested to quantify the potential benefits of a fully-wet biomass supply system to a commercial biorefinery.

Compatibility of High-Moisture Storage for Biochemical Conversion of Corn Stover: Storage Performance at Laboratory and Field Scales

PubMed Central

Wendt, Lynn M.; Murphy, J. Austin; Smith, William A.; Robb, Thomas; Reed, David W.; Ray, Allison E.; Liang, Ling; He, Qian; Sun, Ning; Hoover, Amber N.; Nguyen, Quang A.

2018-01-01

Wet anaerobic storage of corn stover can provide a year-round supply of feedstock to biorefineries meanwhile serving an active management approach to reduce the risks associated with fire loss and microbial degradation. Wet logistics systems employ particle size reduction early in the supply chain through field-chopping which removes the dependency on drying corn stover prior to baling, expands the harvest window, and diminishes the biorefinery size reduction requirements. Over two harvest years, in-field forage chopping was capable of reducing over 60% of the corn stover to a particle size of 6 mm or less. Aerobic and anaerobic storage methods were evaluated for wet corn stover in 100 L laboratory reactors. Of the methods evaluated, traditional ensiling resulted in <6% total solid dry matter loss (DML), about five times less than the aerobic storage process and slightly less than half that of the anaerobic modified-Ritter pile method. To further demonstrate the effectiveness of the anaerobic storage, a field demonstration was completed with 272 dry tonnes of corn stover; DML averaged <5% after 6 months. Assessment of sugar release as a result of dilute acid or dilute alkaline pretreatment and subsequent enzymatic hydrolysis suggested that when anaerobic conditions were maintained in storage, sugar release was either similar to or greater than as-harvested material depending on the pretreatment chemistry used. This study demonstrates that wet logistics systems offer practical benefits for commercial corn stover supply, including particle size reduction during harvest, stability in storage, and compatibility with biochemical conversion of carbohydrates for biofuel production. Evaluation of the operational efficiencies and costs is suggested to quantify the potential benefits of a fully-wet biomass supply system to a commercial biorefinery. PMID:29632861

Enzymatic production of xylooligosaccharides from corn stover and corn cobs treated with aqueous ammonia.

PubMed

Zhu, Yongming; Kim, Tae Hyun; Lee, Y Y; Chen, Rongfu; Elander, Richard T

2006-01-01

A novel method of producing food-grade xylooligosaccharides from corn stover and corn cobs was investigated. The process starts with pretreatment of feedstock in aqueous ammonia, which results delignified and xylan-rich substrate. The pretreated substrates are subjected to enzymatic hydrolysis of xylan using endoxylanase for production of xylooligosaccharides. The conventional enzyme-based method involves extraction of xylan with a strong alkaline solution to form a liquid intermediate containing soluble xylan. This intermediate is heavily contaminated with various extraneous components. A costly purification step is therefore required before enzymatic hydrolysis. In the present method, xylan is obtained in solid form after pretreatment. Water-washing is all that is required for enzymatic hydrolysis of this material. The complex step of purifying soluble xylan from contaminant is essentially eliminated. Refining of xylooligosaccharides to food-grade is accomplished by charcoal adsorption followed by ethanol elution. Xylanlytic hydrolysis of the pretreated corn stover yielded glucan-rich residue that is easily digestible by cellulase enzyme. The digestibility of the residue reached 86% with enzyme loading of 10 filter paper units/g-glucan. As a feedstock for xylooligosaccharides production, corn cobs are superior to corn stover because of high xylan content and high packing density. The high packing density of corn cobs reduces water input and eventually raises the product concentration.

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%.

Pretreatment of corn stover using wet oxidation to enhance enzymatic digestibility.

PubMed

Varga, Eniko; Schmidt, Anette S; Réczey, Kati; Thomsen, Anne Belinda

2003-01-01

Corn stover is an abundant, promising raw material for fuel ethanol production. Although it has a high cellulose content, without pretreatment it resists enzymatic hydrolysis, like most lignocellulosic materials. Wet oxidation (water, oxygen, mild alkali or acid, elevated temperature and pressure) was investigated to enhance the enzymatic digestibility of corn stover. Six different combinations of reaction temperature, time, and pH were applied. The best conditions (60 g/L of corn stover, 195 degrees C, 15 min, 12 bar O2, 2 g/L of Na2CO3) increased the enzymatic conversion of corn stover four times, compared to untreated material. Under these conditions 60% of hemicellulose and 30% of lignin were solubilized, whereas 90% of cellulose remained in the solid fraction. After 24-h hydrolysis at 50 degrees C using 25 filter paper units (FPU)/g of drymatter (DM) biomass, the achieved conversion of cellulose to glucose was about 85%. Decreasing the hydrolysis temperature to 40 degrees C increased hydrolysis time from 24 to 72 h. Decreasing the enzyme loading to 5 FPU/g of DM biomass slightly decreased the enzymatic conversion from 83.4 to 71%. Thus, enzyme loading can be reduced without significantly affecting the efficiency of hydrolysis, an important economical aspect.

Recycling the liquid fraction of alkaline hydrogen peroxide in the pretreatment of corn stover.

PubMed

Alencar, Bárbara Ribeiro Alves; Reis, Alexandre Libanio Silva; de Souza, Raquel de Fatima Rodrigues; Morais, Marcos Antônio; Menezes, Rômulo Simões Cezar; Dutra, Emmanuel Damilano

2017-10-01

The aim of this study was to evaluate the influence of recycling the liquid fraction of pretreatment with alkaline hydrogen peroxide (AHP) on the hydrolysis of corn stover. Corn stover was pretreated in the traditional condition with 7.5% v/v H 2 O 2 . After pretreatment, the solids were separated from the liquid fraction and five successive reuse cycles of the liquid fraction were tested. The solid fraction from pretreatment in each recycle was submitted to enzymatic hydrolysis. The number of recycles had a linear negative effect (R 2 =0.98) on biomass delignification efficiency and also affected negatively the enzymatic conversion efficiency. Despite the decrease in efficiency after each recycling step, reuse of the liquid fraction leads to reduction in water, H 2 O 2 and NaOH consumption of up to 57.6%, 59.6% and 57.6%, respectively. These findings point to an efficient recycling technology, which may reduce costs and save water. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biological abatement of cellulase inhibitors.

PubMed

Cao, Guangli; Ximenes, Eduardo; Nichols, Nancy N; Zhang, Leyu; Ladisch, Michael

2013-10-01

Removal of enzyme inhibitors released during lignocellulose pretreatment is essential for economically feasible biofuel production. We tested bio-abatement to mitigate enzyme inhibitor effects observed in corn stover liquors after pretreatment with either dilute acid or liquid hot water at 10% (w/v) solids. Bio-abatement of liquors was followed by enzymatic hydrolysis of cellulose. To distinguish between inhibitor effects on enzymes and recalcitrance of the substrate, pretreated corn stover solids were removed and replaced with 1% (w/v) Solka Floc. Cellulose conversion in the presence of bio-abated liquors from dilute acid pretreatment was 8.6% (0.1x enzyme) and 16% (1x enzyme) higher than control (non-abated) samples. In the presence of bio-abated liquor from liquid hot water pretreated corn stover, 10% (0.1x enzyme) and 13% (1x enzyme) higher cellulose conversion was obtained compared to control. Bio-abatement yielded improved enzyme hydrolysis in the same range as that obtained using a chemical (overliming) method for mitigating inhibitors. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

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

Effect of the molecular structure of lignin-based polyoxyethylene ether on enzymatic hydrolysis efficiency and kinetics of lignocelluloses.

PubMed

Lin, Xuliang; Qiu, Xueqing; Zhu, Duming; Li, Zihao; Zhan, Ningxin; Zheng, Jieyi; Lou, Hongming; Zhou, Mingsong; Yang, Dongjie

2015-10-01

Effect of the molecular structure of lignin-based polyoxyethylene ether (EHL-PEG) on enzymatic hydrolysis of Avicel and corn stover was investigated. With the increase of PEG contents and molecular weight of EHL-PEG, glucose yield of corn stover increased. EHL-PEG enhanced enzymatic hydrolysis of corn stover significantly at buffer pH 4.8-5.5. Glucose yield of corn stover at 20% solid content increased from 32.8% to 63.8% by adding EHL-PEG, while that with PEG4600 was 54.2%. Effect of EHL-PEG on enzymatic hydrolysis kinetics of cellulose film was studied by quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM). An enhancing mechanism of EHL-PEG on enzymatic hydrolysis kinetics of cellulose was proposed. Cellulase aggregates dispersed by EHL-PEG excavated extensive cavities into the surface of cellulose film, making the film become more loose and exposed. After the maximum enzymatic hydrolysis rate, the film was mainly peeled off layer by layer until equilibrium. Copyright © 2015 Elsevier Ltd. All rights reserved.

Enhanced biohydrogen production from corn stover by the combination of Clostridium cellulolyticum and hydrogen fermentation bacteria.

PubMed

Zhang, Shou-Chi; Lai, Qi-Heng; Lu, Yuan; Liu, Zhi-Dan; Wang, Tian-Min; Zhang, Chong; Xing, Xin-Hui

2016-10-01

Hydrogen was produced from steam-exploded corn stover by using a combination of the cellulolytic bacterium Clostridium cellulolyticum and non-cellulolytic hydrogen-producing bacteria. The highest hydrogen yield of the co-culture system with C. cellulolyticum and Citrobacter amalonaticus reached 51.9 L H2/kg total solid (TS). The metabolites from the co-culture system were significantly different from those of the mono-culture systems. Formate, which inhibits the growth of C. cellulolyticum, could be consumed by the hydrogen-evolving bacteria, and transformed into hydrogen. Glucose and xylose were released from corn stover via hydrolysis by C. cellulolyticum and were quickly utilized in dark fermentation with the co-cultured hydrogen-producing bacteria. Because the hydrolysis of corn stover by C. cellulolyticum was much slower than the utilization of glucose and xylose by the hydrogen-evolving bacteria, the sugar concentrations were always maintained at low levels, which favored a high hydrogen molar yield. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

75 FR 68214 - Flubendiamide; Pesticide Tolerances; Technical Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-05

... established tolerances for corn, field, grain; corn, field, stover; corn, sweet, stover; and cotton gin... ppm); corn, sweet, stover (0.25 ppm); and cotton gin byproducts (0.60 ppm). As supported by submitted..., stover; corn, sweet, stover; and cotton gin byproducts in the table in Sec. 180.369(a)(1). III. Why is...

76 FR 16308 - Dichlormid; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-23

..., stover; corn, pop, grain; corn, pop, stover; corn, sweet, forage; corn, sweet, kernel plus cob with husks... sweet corn forage, kernel plus cob with husks removed, and stover at 0.05 ppm. EPA has extended the..., sweet, forage; corn, sweet, kernel plus cob with husks removed; and corn, sweet, stover at 0.05 ppm...

Enhancing the enzymatic hydrolysis of corn stover by an integrated wet-milling and alkali pretreatment.

PubMed

He, Xun; Miao, Yelian; Jiang, Xuejian; Xu, Zidong; Ouyang, Pingkai

2010-04-01

An integrated wet-milling and alkali pretreatment was applied to corn stover prior to enzymatic hydrolysis. The effects of NaOH concentration in the pretreatment on crystalline structure, chemical composition, and reducing-sugar yield of corn stover were investigated, and the mechanism of increasing reducing-sugar yield by the pretreatment was discussed. The experimental results showed that the crystalline structure of corn stover was disrupted, and lignin was removed, while cellulose and hemicellulose were retained in corn stover by the pretreatment with 1% NaOH in 1 h. The reducing-sugar yield from the pretreated corn stovers increased from 20.2% to 46.7% when the NaOH concentration increased from 0% to 1%. The 1% NaOH pretreated corn stover had a holocellulose conversion of 55.1%. The increase in reducing-sugar yield was related to the crystalline structure disruption and delignification of corn stover. It was clarified that the pretreatment significantly enhanced the conversion of cellulose and hemicellulose in the corn stover to sugars.

The impacts of deacetylation prior to dilute acid pretreatment on the bioethanol process

PubMed Central

2012-01-01

Background Dilute acid pretreatment is a promising pretreatment technology for the biochemical production of ethanol from lignocellulosic biomass. During dilute acid pretreatment, xylan depolymerizes to form soluble xylose monomers and oligomers. Because the xylan found in nature is highly acetylated, the formation of xylose monomers requires two steps: 1) cleavage of the xylosidic bonds, and 2) cleavage of covalently bonded acetyl ester groups. Results In this study, we show that the latter may be the rate limiting step for xylose monomer formation. Furthermore, acetyl groups are also found to be a cause of biomass recalcitrance and hydrolyzate toxicity. While the removal of acetyl groups from native corn stover by alkaline de-esterification prior to pretreatment improves overall process yields, the exact impact is highly dependent on the corn stover variety in use. Xylose monomer yields in pretreatment generally increases by greater than 10%. Compared to pretreated corn stover controls, the deacetylated corn stover feedstock is approximately 20% more digestible after pretreatment. Finally, by lowering hydrolyzate toxicity, xylose utilization and ethanol yields are further improved during fermentation by roughly 10% and 7%, respectively. In this study, several varieties of corn stover lots were investigated to test the robustness of the deacetylation-pretreatment-saccharification-fermentation process. Conclusions Deacetylation shows significant improvement on glucose and xylose yields during pretreatment and enzymatic hydrolysis, but it also reduces hydrolyzate toxicity during fermentation, thereby improving ethanol yields and titer. The magnitude of effect is dependent on the selected corn stover variety, with several varieties achieving improvements of greater than 10% xylose yield in pretreatment, 20% glucose yield in low solids enzymatic hydrolysis and 7% overall ethanol yield. PMID:22369467

Multipass rotary shear comminution process to produce corn stover particles

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

Dooley, James H; Lanning, David N

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.

40 CFR 180.565 - Thiamethoxam; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

....20 Corn, field, forage 0.10 Corn, field, stover 0.05 Corn, pop, forage 0.10 Corn, pop, stover 0.05 Corn, sweet, forage 0.10 Corn, sweet, kernel plus cob with husks removed 0.02 Corn, sweet, stover 0.05...

40 CFR 180.565 - Thiamethoxam; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

....20 Corn, field, forage 0.10 Corn, field, stover 0.05 Corn, pop, forage 0.10 Corn, pop, stover 0.05 Corn, sweet, forage 0.10 Corn, sweet, kernel plus cob with husks removed 0.02 Corn, sweet, stover 0.05...

40 CFR 180.565 - Thiamethoxam; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

....05 Corn, field, forage 0.10 Corn, field, stover 0.05 Corn, pop, forage 0.10 Corn, pop, stover 0.05 Corn, sweet, forage 0.10 Corn, sweet, kernel plus cob with husks removed 0.02 Corn, sweet, stover 0.05...

Viscoelastic properties of microfibrillated cellulose (MFC) produced from agricultural residue corn stover

USDA-ARS?s Scientific Manuscript database

The rheological properties of microfibrillated cellulose (MFC) produced from agricultural residue corn stover were investigated. The corn stover MFC gels exhibited concentration-dependent viscoelastic properties. Higher corn stover MFC concentrations resulted in stronger viscoelastic properties. Th...

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. [75 FR 6576, Feb. 10, 2010] ...

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. [75 FR 6576, Feb. 10, 2010] ...

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. [75 FR 6576, Feb. 10, 2010] ...

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. [75 FR 6576, Feb. 10, 2010] ...

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. [75 FR 6576, Feb. 10, 2010] ...

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.

Life Cycle Assessment of high ligno-cellulosic biomass pyrolysis coupled with anaerobic digestion.

PubMed

Righi, Serena; Bandini, Vittoria; Marazza, Diego; Baioli, Filippo; Torri, Cristian; Contin, Andrea

2016-07-01

A Life Cycle Assessment is conducted on pyrolysis coupled to anaerobic digestion to treat corn stovers and to obtain bioenergy and biochar. The analysis takes into account the feedstock treatment process, the fate of products and the indirect effects due to crop residue removal. The biochar is considered to be used as solid fuel for coal power plants or as soil conditioner. All results are compared with a corresponding fossil-fuel-based scenario. It is shown that the proposed system always enables relevant primary energy savings of non-renewable sources and a strong reduction of greenhouse gases emissions without worsening the abiotic resources depletion. Conversely, the study points out that the use of corn stovers for mulch is critical when considering acidification and eutrophication impacts. Therefore, removal of corn stovers from the fields must be planned carefully. Copyright © 2016. Published by Elsevier Ltd.

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 in...

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 in...

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 in...

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 in...

40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 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, when applied/used as an antifungal agent. [68 FR 41541, July 14...

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 in...

Reaction Kinetic Model of Dilute Acid-Catalyzed Hemicellulose Hydrolysis of Corn Stover under High-Solid Conditions

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

Shi, Suan; Guan, Wenjian; Kang, Li

High solid conditions are desirable in pretreatment of lignocellulosic biomass. An advanced dilute-acid pretreatment reactor has been developed at National Renewable Energy Laboratory (NREL). It is a continuous auger-driven reactor that can be operated with high-solid charge at high temperature and with short residence time resulting high productivity and high sugar concentration. Here, we investigated the kinetics of the reactions associated with dilute-acid pretreatment of corn stover, covering the reaction conditions of the NREL reactor operation: 155-185 C, 1-2 wt% sulfuric acid concentration, and 1:2 solid to liquid ratio. The experimental data were fitted to a first-order biphasic model whichmore » assumes that xylan is comprised of two different fragments: fast and slow reacting fractions. Due to the high solid loading condition, significant amount of xylose oligomers was observed during the pretreatment. We also included the oligomers as an intermediate entity in the kinetic model. The effect of acid concentration was incorporated into the pre-exponential factor of Arrhenius equation. The kinetic model with bestfit kinetic parameters has shown good agreement with experimental data. The kinetic parameter values of the proposed model were noticeably different from those previously reported. The activation energies of xylan hydrolysis are lower and the acid exponents are higher than the average of literature values. The proposed model can serve as a useful tool for design and operation of pretreatment system pertaining to corn stover.« less

Reaction Kinetic Model of Dilute Acid-Catalyzed Hemicellulose Hydrolysis of Corn Stover under High-Solid Conditions

DOE PAGES

Shi, Suan; Guan, Wenjian; Kang, Li; ...

2017-09-13

High solid conditions are desirable in pretreatment of lignocellulosic biomass. An advanced dilute-acid pretreatment reactor has been developed at National Renewable Energy Laboratory (NREL). It is a continuous auger-driven reactor that can be operated with high-solid charge at high temperature and with short residence time resulting high productivity and high sugar concentration. Here, we investigated the kinetics of the reactions associated with dilute-acid pretreatment of corn stover, covering the reaction conditions of the NREL reactor operation: 155-185 C, 1-2 wt% sulfuric acid concentration, and 1:2 solid to liquid ratio. The experimental data were fitted to a first-order biphasic model whichmore » assumes that xylan is comprised of two different fragments: fast and slow reacting fractions. Due to the high solid loading condition, significant amount of xylose oligomers was observed during the pretreatment. We also included the oligomers as an intermediate entity in the kinetic model. The effect of acid concentration was incorporated into the pre-exponential factor of Arrhenius equation. The kinetic model with bestfit kinetic parameters has shown good agreement with experimental data. The kinetic parameter values of the proposed model were noticeably different from those previously reported. The activation energies of xylan hydrolysis are lower and the acid exponents are higher than the average of literature values. The proposed model can serve as a useful tool for design and operation of pretreatment system pertaining to corn stover.« less

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

PubMed Central

2013-01-01

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

Production of ethanol and furfural from corn stover

USDA-ARS?s Scientific Manuscript database

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...

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, when...

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, when...

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, when...

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

Sievers, David A.; Kuhn, Erik M.; Tucker, Melvin P.

In this study, the reaction conditions used during dilute-acid pretreatment of lignocellulosic biomass control the carbohydrate digestion yield and also hydrolyzate properties. Depending on the conversion route of interest, solid-liquid separation (SLS) may be required to split the hemicellulose-rich liquor from the cellulose-rich insoluble solids, and slurry properties are important for SLS. Corn stover was pretreated at different reaction conditions and the slurries were assessed for conversion yield and filtration performance. Increasing pretreatment temperature reduced the solids mean particle size and resulted in slower slurry filtration rates when vacuum filtered or pressure filtered. Corn stover pretreated at 165 °C formore » 10 min and with 1% H 2SO 4 exhibited the highest xylose yield and best filtration performance with a no-wash filtration rate of 80 kg/h m 2 and cake permeability of 15 x 10 -15.« less

40 CFR 180.549 - Diflufenzopyr; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... diflufenzopyr, in or on the following raw agricultural commodities: Commodity Parts per million Corn, field, forage 0.05 Corn, field, grain 0.05 Corn, field, stover 0.05 Corn, pop, grain 0.05 Corn, pop, stover 0.05 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.05...

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. [Reserved...

40 CFR 180.549 - Diflufenzopyr; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... diflufenzopyr, in or on the following raw agricultural commodities: Commodity Parts per million Corn, field, forage 0.05 Corn, field, grain 0.05 Corn, field, stover 0.05 Corn, pop, grain 0.05 Corn, pop, stover 0.05 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.05...

40 CFR 180.469 - Dichlormid; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Parts per million Corn, field, forage 0.05 Corn, field, grain 0.05 Corn, field, stover 0.05 Corn, pop, grain 0.05 Corn, pop, stover 0.05 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.05 (b) Section 18 emergency exemptions. [Reserved] (c) Tolerances with...

40 CFR 180.486 - Chlorethoxyfos; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) phosphorothioate, in or on the commodity. 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 (b) Section 18 emergency...

40 CFR 180.253 - Methomyl; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Cabbage, Chinese, bok choy 5 Cabbage, Chinese, napa 5 Cauliflower 2 Celery 3 Collards 6 Corn, field, forage 10 Corn, field, grain 0.1 Corn, field, stover 10 Corn, pop, grain 0.1 Corn, pop, stover 10 Corn, sweet, forage 10 Corn, sweet, kernel plus cob with husks removed 0.1(N) Corn, sweet, stover 10 Cotton...

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. [Reserved...

40 CFR 180.639 - Flubendiamide; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... million Almond, hulls 9.0 Apple, wet pomace 5.0 Corn, field, forage 8.0 Corn, field, grain 0.03 Corn, field, stover 15 Corn, pop, grain 0.02 Corn, pop, stover 15 Corn, sweet, forage 9.0 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 25 Cotton gin byproducts 60 Cotton, undelinted...

40 CFR 180.549 - Diflufenzopyr; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... diflufenzopyr, in or on the following raw agricultural commodities: Commodity Parts per million Corn, field, forage 0.05 Corn, field, grain 0.05 Corn, field, stover 0.05 Corn, pop, grain 0.05 Corn, pop, stover 0.05 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.05...

40 CFR 180.486 - Chlorethoxyfos; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) phosphorothioate, in or on the commodity. 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 (b) Section 18 emergency...

40 CFR 180.434 - Propiconazole; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

....05 Cattle, meat byproducts, except liver and kidney 0.05 Cilantro, leaves 13 Citrus, oil 1000 Corn, field, forage 12 Corn, field, grain 0.2 Corn, field, stover 30 Corn, pop, grain 0.2 Corn, pop, stover 30 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with husks removed 0.1 Corn, sweet, stover 30...

40 CFR 180.549 - Diflufenzopyr; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... diflufenzopyr, in or on the following raw agricultural commodities: Commodity Parts per million Corn, field, forage 0.05 Corn, field, grain 0.05 Corn, field, stover 0.05 Corn, pop, grain 0.05 Corn, pop, stover 0.05 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.05...

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. [Reserved...

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. [Reserved...

40 CFR 180.486 - Chlorethoxyfos; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) phosphorothioate, in or on the commodity. 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 (b) Section 18 emergency...

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. [Reserved...

40 CFR 180.169 - Carbaryl; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 70 None Corn, field, forage 30 None Corn, field, grain 0.02 None Corn, field, stover 20 None Corn, pop, grain 0.02 None Corn, pop, stover 20 None Corn, sweet, forage 185 None Corn, sweet, kernel plus cob with husks removed 0.1 None Corn, sweet, stover 215 None Cotton, undelinted seed 5.0 10/31/09...

40 CFR 180.639 - Flubendiamide; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... following commodities: Commodity Parts per million Almond, hulls 9.0 Apple, wet pomace 2.0 Corn, field, forage 8.0 Corn, field, grain 0.03 Corn, field, stover 15 Corn, pop, grain 0.02 Corn, pop, stover 15 Corn, sweet, forage 9.0 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 25 Cotton gin...

40 CFR 180.253 - Methomyl; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Cabbage, Chinese, bok choy 5 Cabbage, Chinese, napa 5 Cauliflower 2 Celery 3 Collards 6 Corn, field, forage 10 Corn, field, grain 0.1 Corn, field, stover 10 Corn, pop, grain 0.1 Corn, pop, stover 10 Corn, sweet, forage 10 Corn, sweet, kernel plus cob with husks removed 0.1(N) Corn, sweet, stover 10 Cotton...

40 CFR 180.169 - Carbaryl; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 70 None Corn, field, forage 30 None Corn, field, grain 0.02 None Corn, field, stover 20 None Corn, pop, grain 0.02 None Corn, pop, stover 20 None Corn, sweet, forage 185 None Corn, sweet, kernel plus cob with husks removed 0.1 None Corn, sweet, stover 215 None Cotton, undelinted seed 5.0 10/31/09...

40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... flavis AF 36 is temporarily exempt from the requirement of a tolerance 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; corn, sweet, stover when used in accordance with the Experimental Use...

40 CFR 180.639 - Flubendiamide; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... million Almond, hulls 9.0 Apple, wet pomace 5.0 Corn, field, forage 8.0 Corn, field, grain 0.03 Corn, field, stover 15 Corn, pop, grain 0.02 Corn, pop, stover 15 Corn, sweet, forage 9.0 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 25 Cotton gin byproducts 60 Cotton, undelinted...

40 CFR 180.469 - Dichlormid; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Parts per million Corn, field, forage 0.05 Corn, field, grain 0.05 Corn, field, stover 0.05 Corn, pop, grain 0.05 Corn, pop, stover 0.05 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.05 (b) Section 18 emergency exemptions. [Reserved] (c) Tolerances with...

40 CFR 180.639 - Flubendiamide; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... following commodities: Commodity Parts per million Almond, hulls 9.0 Apple, wet pomace 2.0 Corn, field, forage 8.0 Corn, field, grain 0.03 Corn, field, stover 15 Corn, pop, grain 0.02 Corn, pop, stover 15 Corn, sweet, forage 9.0 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 25 Cotton gin...

40 CFR 180.469 - Dichlormid; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Parts per million Corn, field, forage 0.05 Corn, field, grain 0.05 Corn, field, stover 0.05 Corn, pop, grain 0.05 Corn, pop, stover 0.05 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.05 (b) Section 18 emergency exemptions. [Reserved] (c) Tolerances with...

40 CFR 180.469 - Dichlormid; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Parts per million Corn, field, forage 0.05 Corn, field, grain 0.05 Corn, field, stover 0.05 Corn, pop, grain 0.05 Corn, pop, stover 0.05 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.05 (b) Section 18 emergency exemptions. [Reserved] (c) Tolerances with...

40 CFR 180.486 - Chlorethoxyfos; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) phosphorothioate, in or on the commodity. 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 (b) Section 18 emergency...

40 CFR 180.169 - Carbaryl; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 70 None Corn, field, forage 30 None Corn, field, grain 0.02 None Corn, field, stover 20 None Corn, pop, grain 0.02 None Corn, pop, stover 20 None Corn, sweet, forage 185 None Corn, sweet, kernel plus cob with husks removed 0.1 None Corn, sweet, stover 215 None Cotton, undelinted seed 5.0 10/31/09...

40 CFR 180.431 - Clopyralid; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Cattle, meat byproducts, except liver 36.0 Corn, field, forage 3.0 Corn, field, grain 1.0 Corn, field, milled byproducts 1.5 Corn, field, stover 10.0 Corn, pop, grain 1.0 Corn, pop, stover 10.0 Corn, sweet, forage 7.0 Corn, sweet, kernel plus cob with husks removed 1.0 Corn, sweet, stover 10.0 Cranberry 4.0 Egg...

40 CFR 180.544 - Methoxyfenozide; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Canistel 0.6 Cattle, fat 0.50 Cattle, meat 0.02 Coriander, leaves 30 Corn, field, forage 15 Corn, field, grain 0.05 Corn, field, refined oil 0.20 Corn, field, stover 125 Corn, pop, grain 0.05 Corn, pop, stover 125 Corn, sweet, forage 30 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 60...

40 CFR 180.220 - Atrazine; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Cattle, meat 0.02 Cattle, meat byproducts 0.02 Corn, field, forage 1.5 Corn, field, grain 0.20 Corn, field, stover 0.5 Corn, pop, forage 1.5 Corn, pop, grain 0.20 Corn, pop, stover 0.5 Corn, sweet, forage 15 Corn, sweet, kernel plus cob with husks removed 0.20 Corn, sweet, stover 2.0 Goat, fat 0.02 Goat...

40 CFR 180.220 - Atrazine; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Cattle, meat 0.02 Cattle, meat byproducts 0.02 Corn, field, forage 1.5 Corn, field, grain 0.20 Corn, field, stover 0.5 Corn, pop, forage 1.5 Corn, pop, grain 0.20 Corn, pop, stover 0.5 Corn, sweet, forage 15 Corn, sweet, kernel plus cob with husks removed 0.20 Corn, sweet, stover 2.0 Goat, fat 0.02 Goat...

40 CFR 180.220 - Atrazine; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Cattle, meat 0.02 Cattle, meat byproducts 0.02 Corn, field, forage 1.5 Corn, field, grain 0.20 Corn, field, stover 0.5 Corn, pop, forage 1.5 Corn, pop, grain 0.20 Corn, pop, stover 0.5 Corn, sweet, forage 15 Corn, sweet, kernel plus cob with husks removed 0.20 Corn, sweet, stover 2.0 Goat, fat 0.02 Goat...

40 CFR 180.431 - Clopyralid; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Cattle, meat byproducts, except liver 36.0 Corn, field, forage 3.0 Corn, field, grain 1.0 Corn, field, milled byproducts 1.5 Corn, field, stover 10.0 Corn, pop, grain 1.0 Corn, pop, stover 10.0 Corn, sweet, forage 7.0 Corn, sweet, kernel plus cob with husks removed 1.0 Corn, sweet, stover 10.0 Cranberry 4.0 Egg...

On-site production of crude glucoamylase for kitchen waste hydrolysis.

PubMed

Wang, Xiao Qiang; Wang, Qun Hui; Liu, Ying Ying; Ma, Hong Zhi

2010-06-01

Kitchen waste from dining rooms accounts for a considerable proportion of municipal solid garbage, and economical recycle ways are needed to be developed. This study investigated glucoamylase production from kitchen waste and the feasibility of kitchen waste hydrolysis by the crude enzymes produced. The key problems of high water content and poor porosity in kitchen waste for glucoamylase production under solid-state fermentation could be solved readily by the addition of corn stover or paddy husk. As a support medium, corn stover was better than paddy husk. Smashed kitchen waste (sKW) mixed with corn stover in the ratio of 3.75 : 1 (dry basis) produced 1838 U g(-1) of glucoamylase by Aspergillus niger UV-60 within 96 h. The enzyme productivity from kitchen waste was over two-fold higher than that from wheat bran with additional nutrients. Without any recovery treatment, the produced glucoamylase could be used directly to hydrolyse sKW slurry. The optimum enzyme dose 8% (crude enzyme/kichen waste, w/w) was not too big, and was sufficient to hydrolyse 10% (dry basis) sKW slurry to produce a maximum amount of reducing sugar of 55.4 g L(-1).

40 CFR 180.555 - Trifloxystrobin; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... pulp 1.0 Citrus, oil 38 Corn, field, forage 6.0 Corn, field, grain 0.05 Corn, field, stover 7 Corn, field, refined oil 0.1 Corn, pop, grain 0.05 Corn, pop, stover 7 Corn, sweet, cannery waste 0.6 Corn, sweet, forage 7.0 Corn, sweet, kernel plus cob with husks removed 0.04 Corn, sweet, stover 4.0 Egg 0.04...

40 CFR 180.555 - Trifloxystrobin; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... pulp 1.0 Citrus, oil 38 Corn, field, forage 6.0 Corn, field, grain 0.05 Corn, field, stover 7 Corn, field, refined oil 0.1 Corn, pop, grain 0.05 Corn, pop, stover 7 Corn, sweet, cannery waste 0.6 Corn, sweet, forage 7.0 Corn, sweet, kernel plus cob with husks removed 0.04 Corn, sweet, stover 4.0 Egg 0.04...

40 CFR 180.555 - Trifloxystrobin; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Corn, field, forage 6.0 Corn, field, grain 0.05 Corn, field, stover 7 Corn, field, refined oil 0.1 Corn, pop, grain 0.05 Corn, pop, stover 7 Corn, sweet, cannery waste 0.6 Corn, sweet, forage 7.0 Corn, sweet, kernel plus cob with husks removed 0.04 Corn, sweet, stover 4.0 Egg 0.04 Fruit, citrus, group 10 0.6...

40 CFR 180.555 - Trifloxystrobin; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Corn, field, forage 6.0 Corn, field, grain 0.05 Corn, field, stover 7 Corn, field, refined oil 0.1 Corn, pop, grain 0.05 Corn, pop, stover 7 Corn, sweet, cannery waste 0.6 Corn, sweet, forage 7.0 Corn, sweet, kernel plus cob with husks removed 0.04 Corn, sweet, stover 4.0 Egg 0.04 Fruit, citrus, group 10 0.6...

Corn stover harvest: Likely effects on soil productivity

USDA-ARS?s Scientific Manuscript database

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...

Production and characterization of cellulose nanofibril (CNF) from agricultural waste corn stover

USDA-ARS?s Scientific Manuscript database

Corn stover, as an agricultural waste, has little economic value. The value-added product cellulose was prepared from corn stover by a relatively simple two-stage process - alkali treatment and bleaching resulting in a >93% purity. The particle size of the corn stover cellulose was reduced by mechan...

40 CFR 180.645 - Thiencarbazone-methyl; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... food and feed commodities: Commodity Parts per million Corn, field, forage 0.04 Corn, field, grain 0.01 Corn, field, stover 0.02 Corn, pop, grain 0.01 Corn, pop, stover 0.01 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 0.05 Wheat, forage 0.10 Wheat, grain...

40 CFR 180.612 - Topramezone; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Parts per million Cattle, kidney 0.05 Cattle, liver 0.15 Corn, field, forage 0.05 Corn, field, grain 0.01 Corn, field, stover 0.05 Corn, pop, grain 0.01 Corn, pop, stover 0.05 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 0.05 Goat, kidney 0.05 Goat...

40 CFR 180.378 - Permethrin; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... byproducts 0.10 Cauliflower 0.5 Cherry, sweet 4.0 Cherry, tart 4.0 Corn, field, forage 50 Corn, field, grain 0.05 Corn, field, stover 30 Corn, pop, grain 0.05 Corn, pop, stover 30 Corn, sweet, forage 50 Corn, sweet, kernel plus cob with husks removed 0.10 Corn, sweet, stover 30 Egg 0.10 Eggplant 0.50 Fruit, pome...

40 CFR 180.571 - Mesotrione; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... agricultural commodities: Commodity Parts per million Asparagus 0.01 Berry, group 13 0.01 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 0.5 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 1.5 Cranberry...

40 CFR 180.213 - Simazine; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Cherry 0.25 Corn, field, forage 0.20 Corn, field, grain 0.20 Corn, field, stover 0.25 Corn, pop, grain 0.20 Corn, pop, stover 0.25 Corn, sweet, forage 0.20 Corn, sweet, kernel plus cob with husks removed 0.25 Corn, sweet, stover 0.25 Cranberry 0.25 Currant 0.25 Egg 0.03 Goat, meat 0.03 Goat, meat...

40 CFR 180.571 - Mesotrione; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... agricultural commodities: Commodity Parts per million Asparagus 0.01 Berry, group 13 0.01 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 0.5 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 1.5 Cranberry...

40 CFR 180.378 - Permethrin; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... byproducts 0.10 Cauliflower 0.5 Cherry, sweet 4.0 Cherry, tart 4.0 Corn, field, forage 50 Corn, field, grain 0.05 Corn, field, stover 30 Corn, pop, grain 0.05 Corn, pop, stover 30 Corn, sweet, forage 50 Corn, sweet, kernel plus cob with husks removed 0.10 Corn, sweet, stover 30 Egg 0.10 Eggplant 0.50 Fruit, pome...

40 CFR 180.612 - Topramezone; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Parts per million Cattle, kidney 0.05 Cattle, liver 0.15 Corn, field, forage 0.05 Corn, field, grain 0.01 Corn, field, stover 0.05 Corn, pop, grain 0.01 Corn, pop, stover 0.05 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 0.05 Goat, kidney 0.05 Goat...

40 CFR 180.645 - Thiencarbazone-methyl; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... food and feed commodities: Commodity Parts per million Corn, field, forage 0.04 Corn, field, grain 0.01 Corn, field, stover 0.02 Corn, pop, grain 0.01 Corn, pop, stover 0.01 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 0.05 Wheat, forage 0.10 Wheat, grain...

40 CFR 180.645 - Thiencarbazone-methyl; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... food and feed commodities: Commodity Parts per million Corn, field, forage 0.04 Corn, field, grain 0.01 Corn, field, stover 0.02 Corn, pop, grain 0.01 Corn, pop, stover 0.01 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 0.05 Wheat, forage 0.10 Wheat, grain...

40 CFR 180.142 - 2,4-D; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

....3 Cattle, meat byproducts, except kidney 0.3 Corn, field, forage 6.0 Corn, field, grain 0.05 Corn, field, stover 50 Corn, pop, grain 0.05 Corn, pop, stover 50 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 50 Cranberry 0.5 Fish 0.1 Fruit, citrus, group 10...

40 CFR 180.262 - Ethoprop; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Cabbage 0.02 Corn, field, forage 0.02 Corn, field, grain 0.02 Corn, field, stover 0.02 Corn, pop, grain 0.02 Corn, pop, stover 0.02 Corn, sweet, forage 0.02 Corn, sweet, kernel plus cob with husks removed 0.02 Corn, sweet, stover 0.02 Cucumber 0.02 Hop, dried cones 0.02 Peppermint, tops 0.02 Pineapple 0.02...

40 CFR 180.378 - Permethrin; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... byproducts 0.10 Cauliflower 0.5 Cherry, sweet 4.0 Cherry, tart 4.0 Corn, field, forage 50 Corn, field, grain 0.05 Corn, field, stover 30 Corn, pop, grain 0.05 Corn, pop, stover 30 Corn, sweet, forage 50 Corn, sweet, kernel plus cob with husks removed 0.10 Corn, sweet, stover 30 Egg 0.10 Eggplant 0.50 Fruit, pome...

40 CFR 180.434 - Propiconazole; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., leaves 13 Citrus, oil 1000 Corn, field, forage 12 Corn, field, grain 0.2 Corn, field, stover 30 Corn, pop, grain 0.2 Corn, pop, stover 30 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with husks removed 0.1 Corn, sweet, stover 30 Fruit, citrus, group 10-10 8.0 Fruit, stone, group 12, except plum 4.0 Goat...

40 CFR 180.213 - Simazine; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Cherry 0.25 Corn, field, forage 0.20 Corn, field, grain 0.20 Corn, field, stover 0.25 Corn, pop, grain 0.20 Corn, pop, stover 0.25 Corn, sweet, forage 0.20 Corn, sweet, kernel plus cob with husks removed 0.25 Corn, sweet, stover 0.25 Cranberry 0.25 Currant 0.25 Egg 0.03 Goat, meat 0.03 Goat, meat...

40 CFR 180.434 - Propiconazole; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., leaves 13 Citrus, oil 1000 Corn, field, forage 12 Corn, field, grain 0.2 Corn, field, stover 30 Corn, pop, grain 0.2 Corn, pop, stover 30 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with husks removed 0.1 Corn, sweet, stover 30 Fruit, citrus, group 10-10 8.0 Fruit, stone, group 12, except plum 4.0 Goat...

40 CFR 180.142 - 2,4-D; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

....3 Cattle, meat byproducts, except kidney 0.3 Corn, field, forage 6.0 Corn, field, grain 0.05 Corn, field, stover 50 Corn, pop, grain 0.05 Corn, pop, stover 50 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 50 Cranberry 0.5 Fish 0.1 Fruit, citrus, group 10...

40 CFR 180.645 - Thiencarbazone-methyl; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... food and feed commodities: Commodity Parts per million Corn, field, forage 0.04 Corn, field, grain 0.01 Corn, field, stover 0.02 Corn, pop, grain 0.01 Corn, pop, stover 0.01 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 0.05 Wheat, forage 0.10 Wheat, grain...

40 CFR 180.571 - Mesotrione; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... agricultural commodities: Commodity Parts per million Asparagus 0.01 Berry, group 13 0.01 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 0.5 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 1.5 Cranberry...

40 CFR 180.571 - Mesotrione; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... agricultural commodities: Commodity Parts per million Asparagus 0.01 Berry, group 13 0.01 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 0.5 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 1.5 Cranberry...

40 CFR 180.142 - 2,4-D; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

....3 Cattle, meat byproducts, except kidney 0.3 Corn, field, forage 6.0 Corn, field, grain 0.05 Corn, field, stover 50 Corn, pop, grain 0.05 Corn, pop, stover 50 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 50 Cranberry 0.5 Fish 0.1 Fruit, citrus, group 10...

40 CFR 180.213 - Simazine; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Cherry 0.25 Corn, field, forage 0.20 Corn, field, grain 0.20 Corn, field, stover 0.25 Corn, pop, grain 0.20 Corn, pop, stover 0.25 Corn, sweet, forage 0.20 Corn, sweet, kernel plus cob with husks removed 0.25 Corn, sweet, stover 0.25 Cranberry 0.25 Currant 0.25 Egg 0.03 Goat, meat 0.03 Goat, meat...

40 CFR 180.213 - Simazine; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Cherry 0.25 Corn, field, forage 0.20 Corn, field, grain 0.20 Corn, field, stover 0.25 Corn, pop, grain 0.20 Corn, pop, stover 0.25 Corn, sweet, forage 0.20 Corn, sweet, kernel plus cob with husks removed 0.25 Corn, sweet, stover 0.25 Cranberry 0.25 Currant 0.25 Egg 0.03 Goat, meat 0.03 Goat, meat...

40 CFR 180.582 - Pyraclostrobin; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 12.5 Citrus, oil 9.0 Coffee, bean, green 0.31 Corn, field, forage 5.0 Corn, field, grain 0.1 Corn, field, refined oil 0.2 Corn, field, stover 17.0 Corn, pop, grain 0.1 Corn, pop, stover 17.0 Corn, sweet, forage 5.0 Corn, sweet, kernel plus cob with husks removed 0.04 Corn, sweet, stover 23.0 Cotton, gin...

40 CFR 180.220 - Atrazine; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Cattle, meat 0.02 Cattle, meat byproducts 0.02 Corn, field, forage 15 Corn, field, grain 0.20 Corn, field, stover 0.5 Corn, pop, forage 1.5 Corn, pop, grain 0.20 Corn, pop, stover 0.5 Corn, sweet, forage 15 Corn, sweet, kernel plus cob with husks removed 0.20 Corn, sweet, stover 2.0 Goat, fat 0.02 Goat, meat 0.02...

40 CFR 180.582 - Pyraclostrobin; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 12.5 Citrus, oil 9.0 Coffee, bean, green 0.31 Corn, field, forage 5.0 Corn, field, grain 0.1 Corn, field, refined oil 0.2 Corn, field, stover 17.0 Corn, pop, grain 0.1 Corn, pop, stover 17.0 Corn, sweet, forage 5.0 Corn, sweet, kernel plus cob with husks removed 0.04 Corn, sweet, stover 23.0 Cotton, gin...

40 CFR 180.220 - Atrazine; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Cattle, meat 0.02 Cattle, meat byproducts 0.02 Corn, field, forage 15 Corn, field, grain 0.20 Corn, field, stover 0.5 Corn, pop, forage 1.5 Corn, pop, grain 0.20 Corn, pop, stover 0.5 Corn, sweet, forage 15 Corn, sweet, kernel plus cob with husks removed 0.20 Corn, sweet, stover 2.0 Goat, fat 0.02 Goat, meat 0.02...

Cellulosic Biomass Sugars to Advantaged Jet Fuel – Catalytic Conversion of Corn Stover to Energy Dense, Low Freeze Point Paraffins and Naphthenes

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

Cortright, Randy

The purpose of this project was to demonstrate the technical and commercial feasibility of producing liquid fuels, particularly jet fuel, from lignocellulosic materials, such as corn stover. This project was led by Virent, Inc. (Virent) which has developed a novel chemical catalytic process (the BioForming ® platform) capable of producing “direct replacement” liquid fuels from biomass-derived feedstocks. Virent has shown it is possible to produce an advantaged jet fuel from biomass that meets or exceeds specifications for commercial and military jet fuel through Fuel Readiness Level (FRL) 5, Process Validation. This project leveraged The National Renewable Energy Lab’s (NREL) expertisemore » in converting corn stover to sugars via dilute acid pretreatment and enzymatic hydrolysis. NREL had previously developed this deconstruction technology for the conversion of corn stover to ethanol. In this project, Virent and NREL worked together to condition the NREL generated hydrolysate for use in Virent’s catalytic process through solids removal, contaminant reduction, and concentration steps. The Idaho National Laboratory (INL) was contracted in this project for the procurement, formatting, storage and analysis of corn stover and Northwestern University developed fundamental knowledge of lignin deconstruction that can help improve overall carbon recovery of the combined technologies. Virent conducted fundamental catalytic studies to improve the performance of the catalytic process and NREL provided catalyst characterization support. A technoeconomic analysis (TEA) was conducted at each stage of the project, with results from these analyses used to inform the direction of the project.« less

40 CFR 180.301 - Carboxin; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Cattle, fat 0.05 Cattle, meat byproducts 0.1 Cattle, meat 0.05 Corn, field, forage 0.2 Corn, field, grain 0.2 Corn, field, stover 0.2 Corn, pop, grain 0.2 Corn, pop, stover 0.2 Corn, sweet, forage 0.2 Corn, sweet, kernel plus cob with husks removed 0.2 Corn, sweet, stover 0.2 Cotton, undelinted seed 0.2 Egg 0...

40 CFR 180.418 - Cypermethrin and an isomer zeta-cypermethrin; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 10 Citrus, dried pulp 1.8 Citrus, oil 4.0 Corn, field, forage 0.20 Corn, field, grain 0.05 Corn, field, stover 3.00 Corn, pop, grain 0.05 Corn, pop, stover 3.00 Corn, sweet, forage 15.00 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 15.00 Cotton, undelinted seed 0.5 Crambe...

40 CFR 180.418 - Cypermethrin and an isomer zeta-cypermethrin; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 10 Citrus, dried pulp 1.8 Citrus, oil 4.0 Corn, field, forage 0.20 Corn, field, grain 0.05 Corn, field, stover 3.00 Corn, pop, grain 0.05 Corn, pop, stover 3.00 Corn, sweet, forage 15.00 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 15.00 Cotton, undelinted seed 0.5 Crambe...

40 CFR 180.352 - Terbufos; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... million Banana 0.025 Beet, sugar, roots 0.05 Beet, sugar, tops 0.1 Coffee, green bean 1 0.05 Corn, field, forage 0.5 Corn, field, grain 0.5 Corn, field, stover 0.5 Corn, pop, grain 0.5 Corn, pop, stover 0.5 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, forage 0.5 Corn, sweet, stover 0.5 Sorghum...

40 CFR 180.352 - Terbufos; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... million Banana 0.025 Beet, sugar, roots 0.05 Beet, sugar, tops 0.1 Coffee, green bean 1 0.05 Corn, field, forage 0.5 Corn, field, grain 0.5 Corn, field, stover 0.5 Corn, pop, grain 0.5 Corn, pop, stover 0.5 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, forage 0.5 Corn, sweet, stover 0.5 Sorghum...

40 CFR 180.352 - Terbufos; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... million Banana 0.025 Beet, sugar, roots 0.05 Beet, sugar, tops 0.1 Coffee, green bean 1 0.05 Corn, field, forage 0.5 Corn, field, grain 0.5 Corn, field, stover 0.5 Corn, pop, grain 0.5 Corn, pop, stover 0.5 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, forage 0.5 Corn, sweet, stover 0.5 Sorghum...

40 CFR 180.352 - Terbufos; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... million Banana 0.025 Beet, sugar, roots 0.05 Beet, sugar, tops 0.1 Coffee, green bean 1 0.05 Corn, field, forage 0.5 Corn, field, grain 0.5 Corn, field, stover 0.5 Corn, pop, grain 0.5 Corn, pop, stover 0.5 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, forage 0.5 Corn, sweet, stover 0.5 Sorghum...

40 CFR 180.301 - Carboxin; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Cattle, fat 0.05 Cattle, meat byproducts 0.1 Cattle, meat 0.05 Corn, field, forage 0.2 Corn, field, grain 0.2 Corn, field, stover 0.2 Corn, pop, grain 0.2 Corn, pop, stover 0.2 Corn, sweet, forage 0.2 Corn, sweet, kernel plus cob with husks removed 0.2 Corn, sweet, stover 0.2 Cotton, undelinted seed 0.2 Egg 0...

40 CFR 180.533 - Esfenvalerate; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Cauliflower 0.5 Collards 3.0 Corn, field, forage 15.0 Corn, field, grain 0.02 Corn, field, stover 15.0 Corn, pop, grain 0.02 Corn, pop, stover 15.0 Corn, sweet, forage 15.0 Corn, sweet, kernel plus cob with husks removed 0.1 Corn, sweet, stover 15.0 Cotton, undelinted seed 0.2 Cucumber 0.5 Egg 0.03 Eggplant 0...

40 CFR 180.533 - Esfenvalerate; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Cauliflower 0.5 Collards 3.0 Corn, field, forage 15.0 Corn, field, grain 0.02 Corn, field, stover 15.0 Corn, pop, grain 0.02 Corn, pop, stover 15.0 Corn, sweet, forage 15.0 Corn, sweet, kernel plus cob with husks removed 0.1 Corn, sweet, stover 15.0 Cotton, undelinted seed 0.2 Cucumber 0.5 Egg 0.03 Eggplant 0...

40 CFR 180.533 - Esfenvalerate; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Cauliflower 0.5 Collards 3.0 Corn, field, forage 15.0 Corn, field, grain 0.02 Corn, field, stover 15.0 Corn, pop, grain 0.02 Corn, pop, stover 15.0 Corn, sweet, forage 15.0 Corn, sweet, kernel plus cob with husks removed 0.1 Corn, sweet, stover 15.0 Cotton, undelinted seed 0.2 Cucumber 0.5 Egg 0.03 Eggplant 0...

40 CFR 180.117 - S-Ethyl dipropylthiocarbamate; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 0.4 Beet, sugar, tops 0.5 Clover, forage 0.1 Clover, hay 0.1 Corn, field, forage 0.08 Corn, field, grain 0.08 Corn, field, stover 0.08 Corn, pop, grain 0.08 Corn, pop, stover 0.08 Corn, sweet, forage 0.08 Corn, sweet, kernel plus cob with husks removed 0.08 Corn, sweet, stover 0.08 Cotton, gin...

40 CFR 180.301 - Carboxin; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Cattle, fat 0.05 Cattle, meat byproducts 0.1 Cattle, meat 0.05 Corn, field, forage 0.2 Corn, field, grain 0.2 Corn, field, stover 0.2 Corn, pop, grain 0.2 Corn, pop, stover 0.2 Corn, sweet, forage 0.2 Corn, sweet, kernel plus cob with husks removed 0.2 Corn, sweet, stover 0.2 Cotton, undelinted seed 0.2 Egg 0...

40 CFR 180.533 - Esfenvalerate; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Cauliflower 0.5 Collards 3.0 Corn, field, forage 15.0 Corn, field, grain 0.02 Corn, field, stover 15.0 Corn, pop, grain 0.02 Corn, pop, stover 15.0 Corn, sweet, forage 15.0 Corn, sweet, kernel plus cob with husks removed 0.1 Corn, sweet, stover 15.0 Cotton, undelinted seed 0.2 Cucumber 0.5 Egg 0.03 Eggplant 0...

40 CFR 180.352 - Terbufos; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... million Banana 0.025 Beet, sugar, roots 0.05 Beet, sugar, tops 0.1 Coffee, green bean 1 0.05 Corn, field, forage 0.5 Corn, field, grain 0.5 Corn, field, stover 0.5 Corn, pop, grain 0.5 Corn, pop, stover 0.5 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, forage 0.5 Corn, sweet, stover 0.5 Sorghum...

40 CFR 180.665 - Sedaxane; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., grain 0.01 Barley, hay 0.04 Barley, straw 0.01 Canola, seed 0.01 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 Oat, forage 0.015...

40 CFR 180.117 - S-Ethyl dipropylthiocarbamate; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 0.4 Beet, sugar, tops 0.5 Clover, forage 0.1 Clover, hay 0.1 Corn, field, forage 0.08 Corn, field, grain 0.08 Corn, field, stover 0.08 Corn, pop, grain 0.08 Corn, pop, stover 0.08 Corn, sweet, forage 0.08 Corn, sweet, kernel plus cob with husks removed 0.08 Corn, sweet, stover 0.08 Cotton, gin...

40 CFR 180.301 - Carboxin; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Cattle, fat 0.05 Cattle, meat byproducts 0.1 Cattle, meat 0.05 Corn, field, forage 0.2 Corn, field, grain 0.2 Corn, field, stover 0.2 Corn, pop, grain 0.2 Corn, pop, stover 0.2 Corn, sweet, forage 0.2 Corn, sweet, kernel plus cob with husks removed 0.2 Corn, sweet, stover 0.2 Cotton, undelinted seed 0.2 Egg 0...

40 CFR 180.117 - S-Ethyl dipropylthiocarbamate; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 0.4 Beet, sugar, tops 0.5 Clover, forage 0.1 Clover, hay 0.1 Corn, field, forage 0.08 Corn, field, grain 0.08 Corn, field, stover 0.08 Corn, pop, grain 0.08 Corn, pop, stover 0.08 Corn, sweet, forage 0.08 Corn, sweet, kernel plus cob with husks removed 0.08 Corn, sweet, stover 0.08 Cotton, gin...

40 CFR 180.117 - S-Ethyl dipropylthiocarbamate; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 0.4 Beet, sugar, tops 0.5 Clover, forage 0.1 Clover, hay 0.1 Corn, field, forage 0.08 Corn, field, grain 0.08 Corn, field, stover 0.08 Corn, pop, grain 0.08 Corn, pop, stover 0.08 Corn, sweet, forage 0.08 Corn, sweet, kernel plus cob with husks removed 0.08 Corn, sweet, stover 0.08 Cotton, gin...

40 CFR 180.665 - Sedaxane; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., grain 0.01 Barley, hay 0.04 Barley, straw 0.01 Canola, seed 0.01 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 Oat, forage 0.015...

Performance and techno-economic assessment of several solid-liquid separation technologies for processing dilute-acid pretreated corn stover.

PubMed

Sievers, David A; Tao, Ling; Schell, Daniel J

2014-09-01

Solid-liquid separation of pretreated lignocellulosic biomass slurries is a critical unit operation employed in several different processes for production of fuels and chemicals. An effective separation process achieves good recovery of solute (sugars) and efficient dewatering of the biomass slurry. Dilute acid pretreated corn stover slurries were subjected to pressure and vacuum filtration and basket centrifugation to evaluate the technical and economic merits of these technologies. Experimental performance results were used to perform detailed process simulations and economic analysis using a 2000 tonne/day biorefinery model to determine differences between the various filtration methods and their process settings. The filtration processes were able to successfully separate pretreated slurries into liquor and solid fractions with estimated sugar recoveries of at least 95% using a cake washing process. A continuous vacuum belt filter produced the most favorable process economics. Copyright © 2014 Elsevier Ltd. All rights reserved.

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 [60 FR 49792...

Performance assessment of dilute-acid leaching to improve corn stover quality for thermochemical conversion

DOE PAGES

Aston, John E.; Thompson, David N.; Westover, Tyler L.

2016-08-30

Lignocellulosic biomass is a sustainable energy source that can help meet the increasing demand for biofuels in the United States. However, the quality and availability of such feedstocks greatly affects their suitability for downstream conversion. This work reports the effects of dilute-acid leaching at various solid loadings, temperatures and acid loadings on the quality of a traditional biochemical feedstock, corn stover, as a potential feedstock for thermochemical conversions. At 5 wt% solids, dilute-acid leaching was observed to effectively remove 97.3% of the alkali metals and alkaline earth metals that can negatively affect degradation pathways during pyrolysis and result in greatermore » yield of non-condensable gases. In addition, up to 98.4% of the chlorine and 88.8% of the phosphorus, which can cause equipment corrosion and foul upgrading catalysts, respectively, were removed. At 25°C in the absence of acid, only 6.8% of the alkali metals and alkaline earth metals were removed; however 88.0% of chloride was still removed. The ratio of alkaline/acidic ash species has been suggested to proportionately relate to slagging in biopower applications. The initial alkali/acid ratio of the ash species present in the untreated corn stover was 0.38 (significant slagging risk). At 5 wt% solids, this ratio was decreased to 0.18 (moderate slagging risk) at 0 wt% acid and 90°C, and was decreased to 0.07, 0.08 and 0.06 at 0.5 wt% acid at 25°C, 50°C and 90°C, respectively (little or no slagging risk). Increasing the acid loading to 1.0% only slightly decreased the measured alkali/acid ratio of remaining ash species. Lastly, the results presented here show that a water wash or dilute-acid preprocessing step can improve corn stover quality for pyrolysis, hydrothermal liquefaction and biopower.« less

Performance assessment of dilute-acid leaching to improve corn stover quality for thermochemical conversion

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

Aston, John E.; Thompson, David N.; Westover, Tyler L.

Lignocellulosic biomass is a sustainable energy source that can help meet the increasing demand for biofuels in the United States. However, the quality and availability of such feedstocks greatly affects their suitability for downstream conversion. This work reports the effects of dilute-acid leaching at various solid loadings, temperatures and acid loadings on the quality of a traditional biochemical feedstock, corn stover, as a potential feedstock for thermochemical conversions. At 5 wt% solids, dilute-acid leaching was observed to effectively remove 97.3% of the alkali metals and alkaline earth metals that can negatively affect degradation pathways during pyrolysis and result in greatermore » yield of non-condensable gases. In addition, up to 98.4% of the chlorine and 88.8% of the phosphorus, which can cause equipment corrosion and foul upgrading catalysts, respectively, were removed. At 25°C in the absence of acid, only 6.8% of the alkali metals and alkaline earth metals were removed; however 88.0% of chloride was still removed. The ratio of alkaline/acidic ash species has been suggested to proportionately relate to slagging in biopower applications. The initial alkali/acid ratio of the ash species present in the untreated corn stover was 0.38 (significant slagging risk). At 5 wt% solids, this ratio was decreased to 0.18 (moderate slagging risk) at 0 wt% acid and 90°C, and was decreased to 0.07, 0.08 and 0.06 at 0.5 wt% acid at 25°C, 50°C and 90°C, respectively (little or no slagging risk). Increasing the acid loading to 1.0% only slightly decreased the measured alkali/acid ratio of remaining ash species. Lastly, the results presented here show that a water wash or dilute-acid preprocessing step can improve corn stover quality for pyrolysis, hydrothermal liquefaction and biopower.« less

Rheology of corn stover slurries during fermentation to ethanol

NASA Astrophysics Data System (ADS)

Ghosh, Sanchari; Epps, Brenden; Lynd, Lee

2017-11-01

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

40 CFR 180.221 - O-Ethyl S-phenyl ethylphos-phonodithioate; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... Beet, sugar, tops 0.1 Do. Corn, field, forage 0.1 Do. Corn, field, grain 0.1 Do. Corn, field, stover 0.1 Do. Corn, pop, grain 0.1 Do. Corn, pop, stover 0.1 Do. Corn, sweet, forage 0.1 Do. Corn, sweet, kernel plus cob with husks removed 0.1 Do. Corn, sweet, stover 0.1 Do. Peanut 0.1 Do. Peanut, hay 0.1 Do...

40 CFR 180.450 - Beta-(4-Chlorophenoxy)-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; tolerances for...

Code of Federal Regulations, 2010 CFR

2010-07-01

... None Corn, field, forage 0.05 None Corn, field, grain 0.05 None Corn, field, stover 0.05 None Corn, pop, grain 0.05 None Corn, pop, stover 0.05 None Corn, sweet, forage 0.05 None Corn, sweet, kernel plus cob with husks removed 0.05 None Corn, sweet, stover 0.05 None Cotton, undelinted seed 0.02 None Oat...

40 CFR 180.221 - O-Ethyl S-phenyl ethylphos-phonodithioate; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... Beet, sugar, tops 0.1 Do. Corn, field, forage 0.1 Do. Corn, field, grain 0.1 Do. Corn, field, stover 0.1 Do. Corn, pop, grain 0.1 Do. Corn, pop, stover 0.1 Do. Corn, sweet, forage 0.1 Do. Corn, sweet, kernel plus cob with husks removed 0.1 Do. Corn, sweet, stover 0.1 Do. Peanut 0.1 Do. Peanut, hay 0.1 Do...

40 CFR 180.221 - O-Ethyl S-phenyl ethylphos-phonodithioate; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Beet, sugar, tops 0.1 Do. Corn, field, forage 0.1 Do. Corn, field, grain 0.1 Do. Corn, field, stover 0.1 Do. Corn, pop, grain 0.1 Do. Corn, pop, stover 0.1 Do. Corn, sweet, forage 0.1 Do. Corn, sweet, kernel plus cob with husks removed 0.1 Do. Corn, sweet, stover 0.1 Do. Peanut 0.1 Do. Peanut, hay 0.1 Do...

40 CFR 180.450 - Beta-(4-Chlorophenoxy)-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; tolerances for...

Code of Federal Regulations, 2014 CFR

2014-07-01

... None Corn, field, forage 0.05 None Corn, field, grain 0.05 None Corn, field, stover 0.05 None Corn, pop, grain 0.05 None Corn, pop, stover 0.05 None Corn, sweet, forage 0.05 None Corn, sweet, kernel plus cob with husks removed 0.05 None Corn, sweet, stover 0.05 None Cotton, undelinted seed 0.02 None Oat...

40 CFR 180.450 - Beta-(4-Chlorophenoxy)-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; tolerances for...

Code of Federal Regulations, 2011 CFR

2011-07-01

... None Corn, field, forage 0.05 None Corn, field, grain 0.05 None Corn, field, stover 0.05 None Corn, pop, grain 0.05 None Corn, pop, stover 0.05 None Corn, sweet, forage 0.05 None Corn, sweet, kernel plus cob with husks removed 0.05 None Corn, sweet, stover 0.05 None Cotton, undelinted seed 0.02 None Oat...

40 CFR 180.450 - Beta-(4-Chlorophenoxy)-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; tolerances for...

Code of Federal Regulations, 2012 CFR

2012-07-01

... None Corn, field, forage 0.05 None Corn, field, grain 0.05 None Corn, field, stover 0.05 None Corn, pop, grain 0.05 None Corn, pop, stover 0.05 None Corn, sweet, forage 0.05 None Corn, sweet, kernel plus cob with husks removed 0.05 None Corn, sweet, stover 0.05 None Cotton, undelinted seed 0.02 None Oat...

40 CFR 180.312 - 4-Aminopyridine; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... million Expiration/Revocation Date Corn, field, forage 0.1 1/15/06 Corn, field, grain 0.1 1/15/06 Corn, field, stover 0.1 1/15/06 Corn, pop, grain 0.1 1/15/06 Corn, pop, stover 0.1 1/15/06 Corn, sweet, forage 0.1 1/15/06 Corn, sweet, kernel plus cob with husks removed 0.1 1/15/06 Corn, sweet, stover 0.1 1/15...

40 CFR 180.450 - Beta-(4-Chlorophenoxy)-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; tolerances for...

Code of Federal Regulations, 2013 CFR

2013-07-01

... None Corn, field, forage 0.05 None Corn, field, grain 0.05 None Corn, field, stover 0.05 None Corn, pop, grain 0.05 None Corn, pop, stover 0.05 None Corn, sweet, forage 0.05 None Corn, sweet, kernel plus cob with husks removed 0.05 None Corn, sweet, stover 0.05 None Cotton, undelinted seed 0.02 None Oat...

40 CFR 180.259 - Propargite; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Cattle, fat 0.1 Cattle, meat 0.1 Cattle, meat byproducts 0.1 Citrus, oil 30.0 Corn, field, forage 10.0 Corn, field, grain 0.1 Corn, field, stover 10.0 Corn, pop, grain 0.1 Corn, pop, stover 10.0 Corn, sweet, forage 10.0 Corn, sweet, stover 10.0 Cotton, undelinted seed 0.1 Egg 0.1 Goat, fat 0.1 Goat, meat 0.1...

40 CFR 180.259 - Propargite; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Cattle, fat 0.1 Cattle, meat 0.1 Cattle, meat byproducts 0.1 Citrus, oil 30.0 Corn, field, forage 10.0 Corn, field, grain 0.1 Corn, field, stover 10.0 Corn, pop, grain 0.1 Corn, pop, stover 10.0 Corn, sweet, forage 10.0 Corn, sweet, stover 10.0 Cotton, undelinted seed 0.1 Egg 0.1 Goat, fat 0.1 Goat, meat 0.1...

40 CFR 180.259 - Propargite; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Cattle, fat 0.1 Cattle, meat 0.1 Cattle, meat byproducts 0.1 Citrus, oil 30.0 Corn, field, forage 10.0 Corn, field, grain 0.1 Corn, field, stover 10.0 Corn, pop, grain 0.1 Corn, pop, stover 10.0 Corn, sweet, forage 10.0 Corn, sweet, stover 10.0 Cotton, undelinted seed 0.1 Egg 0.1 Goat, fat 0.1 Goat, meat 0.1...

40 CFR 180.259 - Propargite; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Cattle, fat 0.1 Cattle, meat 0.1 Cattle, meat byproducts 0.1 Citrus, oil 30.0 Corn, field, forage 10.0 Corn, field, grain 0.1 Corn, field, stover 10.0 Corn, pop, grain 0.1 Corn, pop, stover 10.0 Corn, sweet, forage 10.0 Corn, sweet, stover 10.0 Cotton, undelinted seed 0.1 Egg 0.1 Goat, fat 0.1 Goat, meat 0.1...

40 CFR 180.259 - Propargite; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Cattle, fat 0.1 Cattle, meat 0.1 Cattle, meat byproducts 0.1 Citrus, oil 30.0 Corn, field, forage 10.0 Corn, field, grain 0.1 Corn, field, stover 10.0 Corn, pop, grain 0.1 Corn, pop, stover 10.0 Corn, sweet, forage 10.0 Corn, sweet, stover 10.0 Cotton, undelinted seed 0.1 Egg 0.1 Goat, fat 0.1 Goat, meat 0.1...

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

PubMed

Varga, Enikõ; Klinke, Helene B; Réczey, Kati; Thomsen, Anne Belinda

2004-12-05

In this study ethanol was produced from corn stover pretreated by alkaline and acidic wet oxidation (WO) (195 degrees C, 15 min, 12 bar oxygen) followed by nonisothermal simultaneous saccharification and fermentation (SSF). In the first step of the SSF, small amounts of cellulases were added at 50 degrees C, the optimal temperature of enzymes, in order to obtain better mixing condition due to some liquefaction. In the second step more cellulases were added in combination with dried baker's yeast (Saccharomyces cerevisiae) at 30 degrees C. The phenols (0.4-0.5 g/L) and carboxylic acids (4.6-5.9 g/L) were present in the hemicellulose rich hydrolyzate at subinhibitory levels, thus no detoxification was needed prior to SSF of the whole slurry. Based on the cellulose available in the WO corn stover 83% of the theoretical ethanol yield was obtained under optimized SSF conditions. This was achieved with a substrate concentration of 12% dry matter (DM) acidic WO corn stover at 30 FPU/g DM (43.5 FPU/g cellulose) enzyme loading. Even with 20 and 15 FPU/g DM (corresponding to 29 and 22 FPU/g cellulose) enzyme loading, ethanol yields of 76 and 73%, respectively, were obtained. After 120 h of SSF the highest ethanol concentration of 52 g/L (6 vol.%) was achieved, which exceeds the technical and economical limit of the industrial-scale alcohol distillation. The SSF results showed that the cellulose in pretreated corn stover can be efficiently fermented to ethanol with up to 15% DM concentration. A further increase of substrate concentration reduced the ethanol yield significant as a result of insufficient mass transfer. It was also shown that the fermentation could be followed with an easy monitoring system based on the weight loss of the produced CO2.

Assessment of Antioxidant and Antimicrobial Properties of Lignin from Corn Stover Residue Pretreated with Low-Moisture Anhydrous Ammonia and Enzymatic Hydrolysis Process.

PubMed

Guo, Mingming; Jin, Tony; Nghiem, Nhuan P; Fan, Xuetong; Qi, Phoebe X; Jang, Chan Ho; Shao, Lingxiao; Wu, Changqing

2018-01-01

Lignin accounts for 15-35% of dry biomass materials. Therefore, developing value-added co-products from lignin residues is increasingly important to improve the economic viability of biofuel production from biomass resources. The main objective of this work was to study the lignin extracts from corn stover residue obtained from a new and improved process for bioethanol production. Extraction conditions that favored high lignin yield were optimized, and antioxidant and antimicrobial activities of the resulting lignin were investigated. Potential estrogenic toxicity of lignin extracts was also evaluated. The corn stover was pretreated by low-moisture anhydrous ammonia (LMAA) and then subjected to enzymatic hydrolysis using cellulase and hemicellulase. The residues were then added with sodium hydroxide and extracted for different temperatures and times for enhancing lignin yield and the bioactivities. The optimal extraction conditions using 4% (w/v) sodium hydroxide were determined to be 50 °C, 120 min, and 1:8 (w:v), the ratio between corn stover solids and extracting liquid. Under the optimal condition, 33.92 g of lignin yield per 100 g of corn stover residue was obtained. Furthermore, the extracts produced using these conditions showed the highest antioxidant activity by the hydrophilic oxygen radical absorbance capacity (ORAC) assay. The extracts also displayed significant antimicrobial activities against Listeria innocua. Minimal estrogenic impacts were observed for all lignin extracts when tested using the MCF-7 cell proliferation assay. Thus, the lignin extracts could be used for antioxidant and antimicrobial applications, and improve the value of the co-products from the biomass-based biorefinery.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pilot-Scale Batch Alkaline Pretreatment of Corn Stover

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

Kuhn, Erik M.; O’Brien, Marykate H.; Ciesielski, Peter N.

The goal of biomass pretreatment is to increase the enzymatic digestibility of the plant cell wall polysaccharides to produce sugars for upgrading to biofuels. Alkaline pretreatment has the ability to solubilize much of the lignin in biomass while the carbohydrates remain insoluble. With an increased research focus to produce high-value products from lignin, a low molecular weight, lignin-rich stream in a biorefinery is desirable. Here, this work reports on batch alkaline pretreatment of corn stover conducted using a three-factor, two-level central composite experimental design in a pilot-scale reactor to determine the relationship between sodium hydroxide (NaOH) loading, temperature, and anthraquinonemore » (AQ) charge on solids solubilization, component yields, and enzymatic digestibility of the residual solids. Operating conditions were 100 to 140 °C, 40 to 70 mg NaOH/g dry corn stover, and 0.05% to 0.2% (w/w) AQ loading. An enzymatic hydrolysis screening study was performed at 2% cellulose loading. Empirical modeling results showed that NaOH loading and temperature are both significant factors, solubilizing 15% to 35% of the solids and up to 54% of the lignin. Enzymatic hydrolysis of the residual solids produced good monomeric glucose (>90%) and xylose (>70%) yields at the more severe pretreatment conditions. We also found that the AQ charge was not a significant factor at the conditions studied, so efforts to reduce xylan and increase lignin solubilization using this compound were not successful. Lastly, while good lignin solubilization was achieved, effectively recovering this stream remains a challenge, and demonstrating performance in continuous reactors is still needed.« less

Pilot-Scale Batch Alkaline Pretreatment of Corn Stover

DOE PAGES

Kuhn, Erik M.; O’Brien, Marykate H.; Ciesielski, Peter N.; ...

2015-12-18

The goal of biomass pretreatment is to increase the enzymatic digestibility of the plant cell wall polysaccharides to produce sugars for upgrading to biofuels. Alkaline pretreatment has the ability to solubilize much of the lignin in biomass while the carbohydrates remain insoluble. With an increased research focus to produce high-value products from lignin, a low molecular weight, lignin-rich stream in a biorefinery is desirable. Here, this work reports on batch alkaline pretreatment of corn stover conducted using a three-factor, two-level central composite experimental design in a pilot-scale reactor to determine the relationship between sodium hydroxide (NaOH) loading, temperature, and anthraquinonemore » (AQ) charge on solids solubilization, component yields, and enzymatic digestibility of the residual solids. Operating conditions were 100 to 140 °C, 40 to 70 mg NaOH/g dry corn stover, and 0.05% to 0.2% (w/w) AQ loading. An enzymatic hydrolysis screening study was performed at 2% cellulose loading. Empirical modeling results showed that NaOH loading and temperature are both significant factors, solubilizing 15% to 35% of the solids and up to 54% of the lignin. Enzymatic hydrolysis of the residual solids produced good monomeric glucose (>90%) and xylose (>70%) yields at the more severe pretreatment conditions. We also found that the AQ charge was not a significant factor at the conditions studied, so efforts to reduce xylan and increase lignin solubilization using this compound were not successful. Lastly, while good lignin solubilization was achieved, effectively recovering this stream remains a challenge, and demonstrating performance in continuous reactors is still needed.« less

Impact of corn stover removal on soil microbial communities in no-till and conventional till continuous corn

USDA-ARS?s Scientific Manuscript database

Corn (Zea mays L.) residue, or stover, can be used as a dry forage replacement in beef cattle diets and is being considered as a feedstock for cellulosic biofuel production. The soil quality and crop productivity ramifications of removing stover, however, likely will depend on stover removal rate an...

40 CFR 180.617 - Metconazole; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

....04 Corn, field, forage 3.0 Corn, field, grain 0.02 Corn, field, stover 4.5 Corn, pop, grain 0.02 Corn, pop, stover 4.5 Corn, sweet, forage 3.0 Corn, sweet, kernel plus cob with husks removed 0.01 Corn...

40 CFR 180.617 - Metconazole; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

....04 Corn, field, forage 3.0 Corn, field, grain 0.02 Corn, field, stover 4.5 Corn, pop, grain 0.02 Corn, pop, stover 4.5 Corn, sweet, forage 3.0 Corn, sweet, kernel plus cob with husks removed 0.01 Corn...

Process development of short-chain polyols synthesis from corn stover by combination of enzymatic hydrolysis and catalytic hydrogenolysis.

PubMed

Fang, Zhen-Hong; Zhang, Jian; Lu, Qi-Ming; Bao, Jie

2014-09-01

Currently short-chain polyols such as ethanediol, propanediol, and butanediol are produced either from the petroleum feedstock or from the starch-based food crop feedstock. In this study, a combinational process of enzymatic hydrolysis with catalytic hydrogenolysis for short-chain polyols production using corn stover as feedstock was developed. The enzymatic hydrolysis of the pretreated corn stover was optimized to produce stover sugars at the minimum cost. Then the stover sugars were purified and hydrogenolyzed into polyols products catalyzed by Raney nickel catalyst. The results show that the yield of short-chain polyols from the stover sugars was comparable to that of the corn-based glucose. The present study provided an important prototype for polyols production from lignocellulose to replace the petroleum- or corn-based polyols for future industrial applications.

40 CFR 180.361 - Pendimethalin; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., oil 0.5 Corn, field, forage 0.1 Corn, field, grain 0.1 Corn, field, stover 0.1 Corn, pop, grain 0.1 Corn, sweet, forage 0.1 Corn, sweet, kernel plus cob with husks removed 0.1 Corn, sweet, stover 0.1...

Steam explosion enhances digestibility and fermentation of corn stover by facilitating ruminal microbial colonization.

PubMed

Zhao, Shengguo; Li, Guodong; Zheng, Nan; Wang, Jiaqi; Yu, Zhongtang

2018-04-01

The purpose of this study was to evaluate steam explosion as a pretreatment to enhance degradation of corn stover by ruminal microbiome. The steam explosion conditions were first optimized, and then the efficacy of steam explosion was evaluated both in vitro and in vivo. Steam explosion altered the physical and chemical structure of corn stover as revealed by scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy, respectively, and increased its cellulose content while decreasing hemicellulose content. Steam-exploded corn stover also increased release of reducing sugars, rate of fermentation, and production of volatile fatty acids (VFAs) in vitro. The steam explosion treatment increased microbial colonization and in situ degradation of cellulose and hemicellulose of corn stover in the rumen of dairy cows. Steam explosion may be a useful pretreatment of corn stover to improve its nutritional value as forage for cattle, or as feedstock for biofuel production. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biological pretreatment of corn stover with ligninolytic enzyme for high efficient enzymatic hydrolysis.

PubMed

Wang, Feng-Qin; Xie, Hui; Chen, Wei; Wang, En-Tao; Du, Feng-Guang; Song, An-Dong

2013-09-01

Aiming at increasing the efficiency of transferring corn stover into sugars, a biological pretreatment was developed and investigated in this study. The protocol was characterized by the pretreatment with crude ligninolytic enzymes from Phanerochete chrysosporium and Coridus versicolor to break the lignin structure in corn stover, followed by a washing procedure to eliminate the inhibition of ligninolytic enzyme on cellulase. By a 2 d-pretreatment, sugar yield from corn stover hydrolysis could be increased by 50.2% (up to 323 mg/g) compared with that of the control. X-ray diffractometry and FT-IR analysis revealed that biological pretreatment could partially remove the lignin of corn stover, and consequently enhance the enzymatic hydrolysis efficiency of cellulose and hemeicellulose. In addition, the amount of microbial inhibitors, such as acetic acid and furfural, were much lower in biological pretreatment than that in acid pretreatment. This study provided a promising pretreatment method for biotransformation of corn stovers. Copyright © 2013 Elsevier Ltd. All rights reserved.

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. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

40 CFR 180.262 - Ethoprop; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., succulent 0.02 Cabbage 0.02 Corn, field, forage 0.02 Corn, field, grain 0.02 Corn, field, stover 0.02 Corn, sweet, forage 0.02 Corn, sweet, kernel plus cob with husks removed 0.02 Corn, sweet, stover 0.02...

40 CFR 180.262 - Ethoprop; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., succulent 0.02 Cabbage 0.02 Corn, field, forage 0.02 Corn, field, grain 0.02 Corn, field, stover 0.02 Corn, sweet, forage 0.02 Corn, sweet, kernel plus cob with husks removed 0.02 Corn, sweet, stover 0.02...

40 CFR 180.262 - Ethoprop; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., succulent 0.02 Cabbage 0.02 Corn, field, forage 0.02 Corn, field, grain 0.02 Corn, field, stover 0.02 Corn, sweet, forage 0.02 Corn, sweet, kernel plus cob with husks removed 0.02 Corn, sweet, stover 0.02...

40 CFR 180.262 - Ethoprop; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., succulent 0.02 Cabbage 0.02 Corn, field, forage 0.02 Corn, field, grain 0.02 Corn, field, stover 0.02 Corn, sweet, forage 0.02 Corn, sweet, kernel plus cob with husks removed 0.02 Corn, sweet, stover 0.02...

75 FR 6576 - Exemption from the Requirement of a Tolerance; Technical Amendment

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-10

... the requirement of a tolerance is established for residues of Aspergillus flavus 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...

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of co-digestion of cucumber residues to corn stover and pig manure ratio on methane production in solid state anaerobic digestion.

PubMed

Wang, Yaya; Li, Guoxue; Chi, Menghao; Sun, Yanbo; Zhang, Jiaxing; Jiang, Shixu; Cui, Zongjun

2018-02-01

This study investigated the performance of co-digesting cucumber residues, corn stover, and pig manure at different ratios. Microbial community structure was analyzed to elucidate functional microorganism contributing to methane production during co-digestion. Results show that mixing cucumber residues with pig manure and corn stover could significantly improved methane yields 1.27-3.46 times higher than mono-feedstock. The methane yields decreased with the cucumber residues increasing when the pig manure ratio was fixed at 4 and 3, and was opposite at ratio 5. The optimal mixture ratio was T2 with the highest methane yield (305.4 mL/g VS) and co-digestion performance index (1.97). The main microbiological community in T2 was bacteria of Firmicutes (44.6%), Bacteroidetes (32.5%), Synergistetes (3.8%) and archaea of Methanosaeta (37.1%), Methanospirillum (18.2%). The mixture ratios changed the microbial community structures. The adding proportion of cucumber residues changed the community composition of the archaea, especially the proportion of Methanosaeta. Copyright © 2017 Elsevier Ltd. All rights reserved.

Maleic acid treatment of bioabated corn stover liquors improves cellulose conversion to ethanol

USDA-ARS?s Scientific Manuscript database

Elimination of inhibitory compounds released during pretreatment of lignocellulose is critical for efficient cellulose conversion and ethanol fermentation. This study examined the effect of bioabated liquor from pretreated corn stover on enzyme hydrolysis of Solka Floc or pretreated corn stover soli...

Sugar loss and enzyme inhibition due to oligosaccharide accumulation during high solids-loading enzymatic hydrolysis

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

Xue, Saisi; Uppugundla, Nirmal; Bowman, Michael J.

Accumulation of recalcitrant oligosaccharides during high-solids loading enzymatic hydrolysis of cellulosic biomass reduces biofuel yields and increases processing costs for a cellulosic biorefinery. Recalcitrant oligosaccharides in AFEX-pretreated corn stover hydrolysate accumulate to the extent of about 18–25 % of the total soluble sugars in the hydrolysate and 12–18 % of the total polysaccharides in the inlet biomass (untreated), equivalent to a yield loss of about 7–9 kg of monomeric sugars per 100 kg of inlet dry biomass (untreated). These oligosaccharides represent a yield loss and also inhibit commercial hydrolytic enzymes, with both being serious bottlenecks for economical biofuel production frommore » cellulosic biomass. Very little is understood about the nature of these oligomers and why they are recalcitrant to commercial enzymes. This work presents a robust method for separating recalcitrant oligosaccharides from high solid loading hydrolysate in gramme quantities. Composition analysis, recalcitrance study and enzyme inhibition study were performed to understand their chemical nature. Results indicate that, oligosaccharide accumulation occurs during high solid loading enzymatic hydrolysis of corn stover (CS) irrespective of using different pretreated corn stover (dilute acid: DA, ionic liquids: IL, and ammonia fibre expansion: AFEX). The methodology for large-scale separation of recalcitrant oligosaccharides from 25 % solids-loading AFEXcorn stover hydrolysate using charcoal fractionation and size exclusion chromatography is reported for the first time. Oligosaccharides with higher degree of polymerization (DP) were recalcitrant towards commercial enzyme mixtures [Ctec2, Htec2 and Multifect pectinase (MP)] compared to lower DP oligosaccharides. Enzyme inhibition studies using processed substrates (Avicel and xylan) showed that low DP oligosaccharides also inhibit commercial enzymes. Addition of monomeric sugars to oligosaccharides increases the inhibitory effects of oligosaccharides on commercial enzymes. In conclusion, the carbohydrate composition of the recalcitrant oligosaccharides, ratios of different DP oligomers and their distribution profiles were determined. Recalcitrance and enzyme inhibition studies help determine whether the commercial enzyme mixtures lack the enzyme activities required to completely de-polymerize the plant cell wall. Such studies clarify the reasons for oligosaccharide accumulation and contribute to strategies by which oligosaccharides can be converted into fermentable sugars and provide higher biofuel yields with less enzyme.« less

Sugar loss and enzyme inhibition due to oligosaccharide accumulation during high solids-loading enzymatic hydrolysis

DOE PAGES

Xue, Saisi; Uppugundla, Nirmal; Bowman, Michael J.; ...

2015-11-26

Accumulation of recalcitrant oligosaccharides during high-solids loading enzymatic hydrolysis of cellulosic biomass reduces biofuel yields and increases processing costs for a cellulosic biorefinery. Recalcitrant oligosaccharides in AFEX-pretreated corn stover hydrolysate accumulate to the extent of about 18–25 % of the total soluble sugars in the hydrolysate and 12–18 % of the total polysaccharides in the inlet biomass (untreated), equivalent to a yield loss of about 7–9 kg of monomeric sugars per 100 kg of inlet dry biomass (untreated). These oligosaccharides represent a yield loss and also inhibit commercial hydrolytic enzymes, with both being serious bottlenecks for economical biofuel production frommore » cellulosic biomass. Very little is understood about the nature of these oligomers and why they are recalcitrant to commercial enzymes. This work presents a robust method for separating recalcitrant oligosaccharides from high solid loading hydrolysate in gramme quantities. Composition analysis, recalcitrance study and enzyme inhibition study were performed to understand their chemical nature. Results indicate that, oligosaccharide accumulation occurs during high solid loading enzymatic hydrolysis of corn stover (CS) irrespective of using different pretreated corn stover (dilute acid: DA, ionic liquids: IL, and ammonia fibre expansion: AFEX). The methodology for large-scale separation of recalcitrant oligosaccharides from 25 % solids-loading AFEXcorn stover hydrolysate using charcoal fractionation and size exclusion chromatography is reported for the first time. Oligosaccharides with higher degree of polymerization (DP) were recalcitrant towards commercial enzyme mixtures [Ctec2, Htec2 and Multifect pectinase (MP)] compared to lower DP oligosaccharides. Enzyme inhibition studies using processed substrates (Avicel and xylan) showed that low DP oligosaccharides also inhibit commercial enzymes. Addition of monomeric sugars to oligosaccharides increases the inhibitory effects of oligosaccharides on commercial enzymes. In conclusion, the carbohydrate composition of the recalcitrant oligosaccharides, ratios of different DP oligomers and their distribution profiles were determined. Recalcitrance and enzyme inhibition studies help determine whether the commercial enzyme mixtures lack the enzyme activities required to completely de-polymerize the plant cell wall. Such studies clarify the reasons for oligosaccharide accumulation and contribute to strategies by which oligosaccharides can be converted into fermentable sugars and provide higher biofuel yields with less enzyme.« less

40 CFR 174.502 - Bacillus thuringiensis Cry1A.105 protein; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... or on the food and feed commodities of corn; corn, field, flour; corn, field, forage; corn, field, grain; corn, field, grits; corn, field, meal; corn, field, refined oil; corn, field, stover; corn, sweet, forage; corn, sweet, kernel plus cob with husk removed; corn, sweet, stover; and corn, pop, grain and...

40 CFR 174.502 - Bacillus thuringiensis Cry1A.105 protein; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... or on the food and feed commodities of corn; corn, field, flour; corn, field, forage; corn, field, grain; corn, field, grits; corn, field, meal; corn, field, refined oil; corn, field, stover; corn, sweet, forage; corn, sweet, kernel plus cob with husk removed; corn, sweet, stover; and corn, pop, grain and...

40 CFR 174.502 - Bacillus thuringiensis Cry1A.105 protein; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2013 CFR

2013-07-01

... or on the food and feed commodities of corn; corn, field, flour; corn, field, forage; corn, field, grain; corn, field, grits; corn, field, meal; corn, field, refined oil; corn, field, stover; corn, sweet, forage; corn, sweet, kernel plus cob with husk removed; corn, sweet, stover; and corn, pop, grain and...

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 of using corn stover to satisfy the RFS.

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

USDA-ARS?s Scientific Manuscript database

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...

Corn stover harvest and tillage impacts on near-surface soil physical quality

USDA-ARS?s Scientific Manuscript database

Excessive harvest of corn (Zea mays L.) stover for ethanol production has raised concerns regarding negative consequences on soil physical quality. Our objective was to quantify the impact of two tillage practices and three levels of corn stover harvest on near-surface soil physical quality through ...

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

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

Schell, Daniel J.; Dowe, Nancy; Chapeaux, Alexandre

This study explored integrated conversion of corn stover to ethanol and highlights techniques for accurate yield calculations. Acid pretreated corn stover (PCS) produced in a pilot-scale reactor was enzymatically hydrolyzed and the resulting sugars were fermented to ethanol by the glucose–xylose fermenting bacteria, Zymomonas mobilis 8b. The calculations account for high solids operation and oligomeric sugars produced during pretreatment, enzymatic hydrolysis, and fermentation, which, if not accounted for, leads to overestimating ethanol yields. The calculations are illustrated for enzymatic hydrolysis and fermentation of PCS at 17.5% and 20.0% total solids achieving 80.1% and 77.9% conversion of cellulose and xylan tomore » ethanol and ethanol titers of 63 g/L and 69 g/L, respectively. In the future, these techniques, including the TEA results, will be applied to fully integrated pilot-scale runs.« less

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

DOE PAGES

Schell, Daniel J.; Dowe, Nancy; Chapeaux, Alexandre; ...

2016-01-19

This study explored integrated conversion of corn stover to ethanol and highlights techniques for accurate yield calculations. Acid pretreated corn stover (PCS) produced in a pilot-scale reactor was enzymatically hydrolyzed and the resulting sugars were fermented to ethanol by the glucose–xylose fermenting bacteria, Zymomonas mobilis 8b. The calculations account for high solids operation and oligomeric sugars produced during pretreatment, enzymatic hydrolysis, and fermentation, which, if not accounted for, leads to overestimating ethanol yields. The calculations are illustrated for enzymatic hydrolysis and fermentation of PCS at 17.5% and 20.0% total solids achieving 80.1% and 77.9% conversion of cellulose and xylan tomore » ethanol and ethanol titers of 63 g/L and 69 g/L, respectively. In the future, these techniques, including the TEA results, will be applied to fully integrated pilot-scale runs.« less

40 CFR 180.570 - Isoxadifen-ethyl; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (safener) in or on the following raw agricultural commodities: Commodity Parts per million Corn, field, forage 0.20 Corn, field, grain 0.08 Corn, field, stover 0.40 Corn, oil 0.50 Corn, pop, grain 0.04 Corn, pop, stover 0.25 Corn, sweet, forage 0.30 Corn, sweet, kernel plus cob with husk removed 0.04 Corn...

40 CFR 180.570 - Isoxadifen-ethyl; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (safener) in or on the following raw agricultural commodities: Commodity Parts per million Corn, field, forage 0.20 Corn, field, grain 0.08 Corn, field, stover 0.40 Corn, oil 0.50 Corn, pop, grain 0.04 Corn, pop, stover 0.25 Corn, sweet, forage 0.30 Corn, sweet, kernel plus cob with husk removed 0.04 Corn...

40 CFR 180.570 - Isoxadifen-ethyl; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (safener) in or on the following raw agricultural commodities: Commodity Parts per million Corn, field, forage 0.20 Corn, field, grain 0.08 Corn, field, stover 0.40 Corn, oil 0.50 Corn, pop, grain 0.04 Corn, pop, stover 0.25 Corn, sweet, forage 0.30 Corn, sweet, kernel plus cob with husk removed 0.04 Corn...

40 CFR 180.570 - Isoxadifen-ethyl; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (safener) in or on the following raw agricultural commodities: Commodity Parts per million Corn, field, forage 0.20 Corn, field, grain 0.08 Corn, field, stover 0.40 Corn, oil 0.50 Corn, pop, grain 0.04 Corn, pop, stover 0.25 Corn, sweet, forage 0.30 Corn, sweet, kernel plus cob with husk removed 0.04 Corn...

40 CFR 180.570 - Isoxadifen-ethyl; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (safener) in or on the following raw agricultural commodities: Commodity Parts per million Corn, field, forage 0.20 Corn, field, grain 0.08 Corn, field, stover 0.40 Corn, oil 0.50 Corn, pop, grain 0.04 Corn, pop, stover 0.25 Corn, sweet, forage 0.30 Corn, sweet, kernel plus cob with husk removed 0.04 Corn...

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

NASA Astrophysics Data System (ADS)

Wilhelm, W. W.; Cushman, J.

2003-12-01

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

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

USDA-ARS?s Scientific Manuscript database

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...

Development of sustainable corn stover harvest strategies for cellulosic ethanol

USDA-ARS?s Scientific Manuscript database

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...

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

USDA-ARS?s Scientific Manuscript database

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...

Life cycle assessment of integrated solid state anaerobic digestion and composting for on-farm organic residues treatment.

PubMed

Li, Yangyang; Manandhar, Ashish; Li, Guoxue; Shah, Ajay

2018-03-20

Driven by the gradual changes in the structure of energy consumption and improvements of living standards in China, the volume of on-farm organic solid waste is increasing. If untreated, these unutilized on-farm organic solid wastes can cause environmental problems. This paper presents the results of a life cycle assessment to compare the environmental impacts of different on-farm organic waste (which includes dairy manure, corn stover and tomato residue) treatment strategies, including anaerobic digestion (AD), composting, and AD followed by composting. The input life cycle inventory data are specific to China. The potential environmental impacts of different waste management strategies were assessed based on their acidification potential (AP), eutrophication potential (EP), global warming potential (GWP), ecotoxicity potential (ETP), and resource depletion (RD). The results show that the preferred treatment strategy for dairy manure is the one that integrated corn stover and tomato residue utilization and solid state AD technologies into the system. The GWP of integrated solid state AD and composting was the least, which is -2900 kg CO 2 eq/ t of dairy manure and approximately 14.8 times less than that of current status (i.e., liquid AD of dairy manure). Solid state AD of dairy manure, corn stover and tomato residues is the most favorable option in terms of AP, EP and ETP, which are more than 40% lower than that of the current status (i.e., AP: 3.11 kg SO 2 , EP: -0.94 kg N, and ETP: -881 CTUe (Comparative Toxic Units ecotoxicity)). The results also show that there is a significant potential for AP, EP, ETP, and GWP reduction, if AD is used prior to composting. The scenario analysis for transportation distance showed that locating the AD plant and composting facility on the farm was advantageous in terms of all the life cycle impact categories. Copyright © 2018 Elsevier Ltd. All rights reserved.

40 CFR 180.470 - Acetochlor; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... stoichiometric equivalents of acetochlor, in or on the following commodities: Commodity Parts per million Corn, field, forage 4.5 Corn, field, grain 0.05 Corn, field, stover 2.5 Corn, pop, grain 0.05 Corn, pop, stover 2.5 Corn, sweet, forage 1.5 Corn, sweet, kernels plus cob with husks removed 0.05 Corn, sweet...

40 CFR 180.350 - Nitrapyrin; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-chloropicolinic acid in or on the following raw agricultural commodities: Commodity Parts per million Corn, field, forage 1.0 Corn, field, grain 0.1 Corn, field, milled byproducts 0.2 Corn, field, stover 1.0 Corn, pop, grain 0.1 Corn, pop, stover 1.0 Corn, sweet, forage 1.0 Corn, sweet, kernel plus cob with husks removed...

40 CFR 180.350 - Nitrapyrin; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-chloropicolinic acid in or on the following raw agricultural commodities: Commodity Parts per million Corn, field, forage 1.0 Corn, field, grain 0.1 Corn, field, milled byproducts 0.2 Corn, field, stover 1.0 Corn, pop, grain 0.1 Corn, pop, stover 1.0 Corn, sweet, forage 1.0 Corn, sweet, kernel plus cob with husks removed...

40 CFR 180.350 - Nitrapyrin; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

...-chloropicolinic acid in or on the following raw agricultural commodities: Commodity Parts per million Corn, field, forage 1.0 Corn, field, grain 0.1 Corn, field, milled byproducts 0.2 Corn, field, stover 1.0 Corn, pop, grain 0.1 Corn, pop, stover 1.0 Corn, sweet, forage 1.0 Corn, sweet, kernel plus cob with husks removed...

40 CFR 180.470 - Acetochlor; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... stoichiometric equivalents of acetochlor, in or on the following commodities: Commodity Parts per million Corn, field, forage 4.5 Corn, field, grain 0.05 Corn, field, stover 2.5 Corn, pop, grain 0.05 Corn, pop, stover 2.5 Corn, sweet, forage 1.5 Corn, sweet, kernels plus cob with husks removed 0.05 Corn, sweet...

40 CFR 180.544 - Methoxyfenozide; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

....0 Canistel 0.6 Cattle, fat 0.50 Cattle, meat 0.02 Citrus, oil 100 Coriander, leaves 30 Corn, field, forage 15 Corn, field, grain 0.05 Corn, field, refined oil 0.20 Corn, field, stover 125 Corn, pop, grain 0.05 Corn, pop, stover 125 Corn, sweet, forage 30 Corn, sweet, kernel plus cob with husks removed 0...

40 CFR 180.470 - Acetochlor; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... stoichiometric equivalents of acetochlor, in or on the following commodities: Commodity Parts per million Corn, field, forage 4.5 Corn, field, grain 0.05 Corn, field, stover 2.5 Corn, pop, grain 0.05 Corn, pop, stover 2.5 Corn, sweet, forage 1.5 Corn, sweet, kernels plus cob with husks removed 0.05 Corn, sweet...

40 CFR 180.612 - Topramezone; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

...)methanone) in or on the following commodities: Commodity Parts permillion Cattle, meat byproducts 0.80 Corn, field, forage 0.05 Corn, field, grain 0.01 Corn, field, stover 0.05 Corn, pop, grain 0.01 Corn, pop, stover 0.05 Corn, sweet, forage 0.05 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet...

40 CFR 180.470 - Acetochlor; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... stoichiometric equivalents of acetochlor, in or on the following commodities: Commodity Parts per million Corn, field, forage 4.5 Corn, field, grain 0.05 Corn, field, stover 2.5 Corn, pop, grain 0.05 Corn, pop, stover 2.5 Corn, sweet, forage 1.5 Corn, sweet, kernels plus cob with husks removed 0.05 Corn, sweet...

40 CFR 180.350 - Nitrapyrin; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-chloropicolinic acid in or on the following raw agricultural commodities: Commodity Parts per million Corn, field, forage 1.0 Corn, field, grain 0.1 Corn, field, milled byproducts 0.2 Corn, field, stover 1.0 Corn, pop, grain 0.1 Corn, pop, stover 1.0 Corn, sweet, forage 1.0 Corn, sweet, kernel plus cob with husks removed...

40 CFR 180.544 - Methoxyfenozide; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 0.6 Cattle, fat 0.50 Cattle, meat 0.02 Cherimoya 0.60 Citrus, oil 100 Corn, field, forage 15 Corn, field, grain 0.05 Corn, field, refined oil 0.20 Corn, field, stover 125 Corn, pop, grain 0.05 Corn, pop, stover 125 Corn, sweet, forage 30 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet...

40 CFR 180.617 - Metconazole; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... byproducts 0.04 Corn, field, forage 3.0 Corn, field, grain 0.02 Corn, field, stover 30 Corn, pop, grain 0.02 Corn, pop, stover 30 Corn, sweet, forage 3.0 Corn, sweet, kernel plus cob with husks removed 0.01 Corn... Soybean, hay 6.0 Soybean, hulls 0.08 Soybean, seed 0.05 Sugarcane, cane 0.06 Vegetable, tuberous and corn...

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. (c) 2009 Wiley Periodicals, Inc.

40 CFR 180.258 - Ametryn; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... agricultural commodities: Commodity Parts per million Expiration/Revocation Date Banana 0.25 6/16/10 Corn, field, forage 0.1 None Corn, field, grain 0.05 None Corn, field, stover 0.05 None Corn, pop, grain 0.05 None Corn, pop, stover 0.05 None Corn, sweet, forage 0.5 6/16/10 Corn, sweet, kernel plus cob with...

40 CFR 180.258 - Ametryn; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... agricultural commodities: Commodity Parts per million Expiration/Revocation Date Banana 0.25 6/16/10 Corn, field, forage 0.1 None Corn, field, grain 0.05 None Corn, field, stover 0.05 None Corn, pop, grain 0.05 None Corn, pop, stover 0.05 None Corn, sweet, forage 0.5 6/16/10 Corn, sweet, kernel plus cob with...

40 CFR 180.258 - Ametryn; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... agricultural commodities: Commodity Parts per million Expiration/Revocation Date Banana 0.25 6/16/10 Corn, field, forage 0.1 None Corn, field, grain 0.05 None Corn, field, stover 0.05 None Corn, pop, grain 0.05 None Corn, pop, stover 0.05 None Corn, sweet, forage 0.5 6/16/10 Corn, sweet, kernel plus cob with...

40 CFR 180.258 - Ametryn; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... agricultural commodities: Commodity Parts per million Expiration/Revocation Date Banana 0.25 6/16/10 Corn, field, forage 0.1 None Corn, field, grain 0.05 None Corn, field, stover 0.05 None Corn, pop, grain 0.05 None Corn, pop, stover 0.05 None Corn, sweet, forage 0.5 6/16/10 Corn, sweet, kernel plus cob with...

40 CFR 180.258 - Ametryn; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... agricultural commodities: Commodity Parts per million Expiration/Revocation Date Banana 0.25 6/16/10 Corn, field, forage 0.1 None Corn, field, grain 0.05 None Corn, field, stover 0.05 None Corn, pop, grain 0.05 None Corn, pop, stover 0.05 None Corn, sweet, forage 0.5 6/16/10 Corn, sweet, kernel plus cob with...

Spatial Analysis of Stover Moisture Content During Harvest Season in the U.S.

DOE PAGES

Oyedeji, Oluwafemi A.; Sokhansanj, Shahab; Webb, Erin

2017-01-01

The moisture content of a maturing crop varies as the harvest season progresses. For crop residues such as corn stover, moisture content at the time of harvest can be as high as 75% (wet mass basis) to less than 20% depending on the geographic location (climate conditions) and stage of harvest. Biomass moisture content is critical for baling and extended storage. It is therefore essential to have an estimate of the quantities of corn stover available as wet or dry for various parts of the U.S. To this end, we analyzed hourly weather data (temperature, humidity, and rainfall) from themore » Typical Meteorological Year v.3 (TMY3) dataset developed by the National Renewable Energy Laboratory. A recently published set of equations for calculating the moisture content of stover as a function of hourly temperature, humidity, and rainfall were used. The annual start and end of corn grain harvest along with annual grain production (in bushels) for each state were extracted from USDA National Agricultural Statistics Service reports. Using these datasets and moisture sorption equations, the percentage of corn stover tonnage with moisture content less than 20%, between 20% and 40%, or greater than 40% was estimated from the length of time that the biomass was in these moisture content ranges. These calculations were carried out for several locations within each of the states for which TMY data were available. It was concluded that about 37.2% of corn stover is dry (<20% moisture content), whereas 36.5% is wet (>40% moisture content) nationwide. The remaining 27.0% of corn stover is between 20% and 40% moisture content. Keywords: Corn stover, Equilibrium moisture content, Field drying, Moisture content, Stover harvest, Typical Meteorological Year data.« less

Spatial Analysis of Stover Moisture Content During Harvest Season in the U.S.

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

Oyedeji, Oluwafemi A.; Sokhansanj, Shahab; Webb, Erin

The moisture content of a maturing crop varies as the harvest season progresses. For crop residues such as corn stover, moisture content at the time of harvest can be as high as 75% (wet mass basis) to less than 20% depending on the geographic location (climate conditions) and stage of harvest. Biomass moisture content is critical for baling and extended storage. It is therefore essential to have an estimate of the quantities of corn stover available as wet or dry for various parts of the U.S. To this end, we analyzed hourly weather data (temperature, humidity, and rainfall) from themore » Typical Meteorological Year v.3 (TMY3) dataset developed by the National Renewable Energy Laboratory. A recently published set of equations for calculating the moisture content of stover as a function of hourly temperature, humidity, and rainfall were used. The annual start and end of corn grain harvest along with annual grain production (in bushels) for each state were extracted from USDA National Agricultural Statistics Service reports. Using these datasets and moisture sorption equations, the percentage of corn stover tonnage with moisture content less than 20%, between 20% and 40%, or greater than 40% was estimated from the length of time that the biomass was in these moisture content ranges. These calculations were carried out for several locations within each of the states for which TMY data were available. It was concluded that about 37.2% of corn stover is dry (<20% moisture content), whereas 36.5% is wet (>40% moisture content) nationwide. The remaining 27.0% of corn stover is between 20% and 40% moisture content. Keywords: Corn stover, Equilibrium moisture content, Field drying, Moisture content, Stover harvest, Typical Meteorological Year data.« less

40 CFR 180.464 - Dimethenamid; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., sugar, dried pulp 0.01 Beet, sugar, molasses 0.01 Beet, sugar, roots 0.01 Beet, sugar, tops 0.01 Corn, field, forage 0.01 Corn, field, grain 0.01 Corn, field, stover 0.01 Corn, pop, forage 0.01 Corn, pop, grain 0.01 Corn, pop, stover 0.01 Corn, sweet, forage 0.01 Corn, sweet, kernel plus cob with husks...

40 CFR 180.470 - Acetochlor; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., sugar, dried pulp 0.50 Beet, sugar, molasses 0.80 Beet, sugar, roots 0.30 Beet, sugar, tops 0.70 Corn, field, forage 4.5 Corn, field, grain 0.05 Corn, field, stover 2.5 Corn, pop, grain 0.05 Corn, pop, stover 2.5 Corn, sweet, forage 1.5 Corn, sweet, kernels plus cob with husks removed 0.05 Corn, sweet...

40 CFR 180.565 - Thiamethoxam; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., meat 0.02 Cattle, meat byproducts 0.04 Citrus, dried pulp 0.60 ppm Coffee, bean, green 1 0.05 Corn, field, forage 0.10 Corn, field, grain 0.020 Corn, field, stover 0.05 Corn, pop, forage 0.10 Corn, pop, grain 0.02 Corn, pop, stover 0.05 Corn, sweet, forage 0.10 Corn, sweet, kernel plus cob with husks...

40 CFR 180.629 - Flutriafol; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... commodities: Commodity Parts per million Corn, sweet, forage 0.09 Corn, sweet, kernel plus cob with husk... Cattle, meat byproducts 0.07 Corn, field, forage 0.75 Corn, field, grain 0.01 Corn, field, refined oil 0.02 Corn, field, stover 1.5 Corn, pop 0.01 Corn, pop, stover 1.5 Fruit, pome, group 11-09 0.40 Fruit...

40 CFR 180.431 - Clopyralid; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Cattle, fat 1.0 Cattle, liver 3.0 Cattle, meat 1.0 Cattle, meat byproducts, except liver 36.0 Corn, field, forage 3.0 Corn, field, grain 1.0 Corn, field, milled byproducts 1.5 Corn, field, stover 10.0 Corn, pop, grain 1.0 Corn, pop, stover 10.0 Corn, sweet, forage 7.0 Corn, sweet, kernel plus cob with husks removed...

40 CFR 180.629 - Flutriafol; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

...)-1H-1,2,4-triazole-1-ethanol) in or on the following commodities: Commodity Parts per million Corn, field, forage 0.09 Corn, field, grain 0.01 Corn, field, refined oil 0.02 Corn, field, stover 0.07 Corn, pop 0.01 Corn, pop, stover 0.07 Corn, sweet, forage 0.09 Corn, sweet, kernel plus cob with husk...

40 CFR 180.464 - Dimethenamid; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., sugar, dried pulp 0.01 Beet, sugar, molasses 0.01 Beet, sugar, roots 0.01 Beet, sugar, tops 0.01 Corn, field, forage 0.01 Corn, field, grain 0.01 Corn, field, stover 0.01 Corn, pop, forage 0.01 Corn, pop, grain 0.01 Corn, pop, stover 0.01 Corn, sweet, forage 0.01 Corn, sweet, kernel plus cob with husks...

40 CFR 180.464 - Dimethenamid; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., sugar, dried pulp 0.01 Beet, sugar, molasses 0.01 Beet, sugar, roots 0.01 Beet, sugar, tops 0.01 Corn, field, forage 0.01 Corn, field, grain 0.01 Corn, field, stover 0.01 Corn, pop, forage 0.01 Corn, pop, grain 0.01 Corn, pop, stover 0.01 Corn, sweet, forage 0.01 Corn, sweet, kernel plus cob with husks...

40 CFR 180.431 - Clopyralid; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Cattle, fat 1.0 Cattle, liver 3.0 Cattle, meat 1.0 Cattle, meat byproducts, except liver 36.0 Corn, field, forage 3.0 Corn, field, grain 1.0 Corn, field, milled byproducts 1.5 Corn, field, stover 10.0 Corn, pop, grain 1.0 Corn, pop, stover 10.0 Corn, sweet, forage 7.0 Corn, sweet, kernel plus cob with husks removed...

40 CFR 180.431 - Clopyralid; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Cattle, fat 1.0 Cattle, liver 3.0 Cattle, meat 1.0 Cattle, meat byproducts, except liver 36.0 Corn, field, forage 3.0 Corn, field, grain 1.0 Corn, field, milled byproducts 1.5 Corn, field, stover 10.0 Corn, pop, grain 1.0 Corn, pop, stover 10.0 Corn, sweet, forage 7.0 Corn, sweet, kernel plus cob with husks removed...

40 CFR 180.609 - Fluoxastrobin; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... of fluoxastrobin. Commodity Parts per million Berry, low growing, subgroup 13-07G 1.9 Corn, field, forage 3.0 Corn, field, grain 0.02 Corn, field, stover 4.5 Corn, sweet, forage 13 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 10 Grain, aspirated grain fractions 60 Leaf...

40 CFR 180.609 - Fluoxastrobin; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... of fluoxastrobin. Commodity Parts per million Berry, low growing, subgroup 13-07G 1.9 Corn, field, forage 3.0 Corn, field, grain 0.02 Corn, field, stover 4.5 Corn, sweet, forage 13 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 10 Grain, aspirated grain fractions 60 Leaf...

40 CFR 180.609 - Fluoxastrobin; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... of fluoxastrobin. Commodity Parts per million Berry, low growing, subgroup 13-07G 1.9 Corn, field, forage 3.0 Corn, field, grain 0.02 Corn, field, stover 4.5 Corn, sweet, forage 13 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 10 Grain, aspirated grain fractions 60 Leaf...

40 CFR 180.609 - Fluoxastrobin; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... of fluoxastrobin. Commodity Parts per million Berry, low growing, subgroup 13-07G 1.9 Corn, field, forage 3.0 Corn, field, grain 0.02 Corn, field, stover 4.5 Corn, sweet, forage 13 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 10 Grain, aspirated grain fractions 60 Leaf...

40 CFR 180.617 - Metconazole; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... byproducts 0.04 Corn, field, forage 3.0 Corn, field, grain 0.02 Corn, field, stover 4.5 Corn, pop, grain 0.02 Corn, pop, stover 4.5 Corn, sweet, forage 3.0 Corn, sweet, kernel plus cob with husks removed 0.01 Corn... Soybean, hay 6.0 Soybean, hulls 0.08 Soybean, seed 0.05 Sugarcane, cane 0.06 Vegetable, tuberous and corn...

40 CFR 180.617 - Metconazole; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... byproducts 0.04 Corn, field, forage 3.0 Corn, field, grain 0.02 Corn, field, stover 4.5 Corn, pop, grain 0.02 Corn, pop, stover 4.5 Corn, sweet, forage 3.0 Corn, sweet, kernel plus cob with husks removed 0.01 Corn... Soybean, hay 6.0 Soybean, hulls 0.08 Soybean, seed 0.05 Sugarcane, cane 0.06 Vegetable, tuberous and corn...

Odorous Volatile Organic Compounds, Escherichia coli, and Nutrient Concentrations when Kiln-Dried Pine Chips and Corn Stover Bedding Are Used in Beef Bedded Manure Packs.

PubMed

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

2017-07-01

Pine ( spp.) bedding has been shown to lower the concentration of odorous volatile organic compounds (VOCs) and pathogenic bacteria compared with corn ( L.) stover bedding, but availability and cost limit the use of pine bedding in cattle confinement facilities. The objectives of this study were to determine if the addition of pine wood chips to laboratory-scaled bedded packs containing corn stover (i) reduced odorous VOC emissions; (ii) reduced total ; and (iii) changed the nutrient composition of the resulting manure-bedded packs. Bedding treatments included 0, 10, 20, 30, 40, 60, 80, and 100% pine chips, with the balance being corn stover. Four bedded packs for each mixture were maintained for 42 d ( = 4 observations per bedding material). The production of total sulfur compounds increased significantly when 100% pine chips were used (44.72 ng L) compared with bedding mixture containing corn stover (18.0-24.56 ng L). The carbon-to-nitrogen ratio exceeded the ideal ratio of 24:1 for the optimum activity of soil microorganisms when ≥60% pine chips (25.3-27.5 ng L) were included in the mixture. The use of 100% pine chips as bedding increased sulfide concentration in the facility 1.8 to 2.4 times over the use of corn stover bedding. was not influenced by the addition of pine chips to the corn stover bedding material but did decrease as the bedded pack aged. Bedding material mixtures containing 30 to 60% pine and 40 to 70% corn stover may be the ideal combination to mitigate odors from livestock facilities using deep bedded systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Effect of steam explosion and microbial fermentation on cellulose and lignin degradation of corn stover.

PubMed

Chang, Juan; Cheng, Wei; Yin, Qingqiang; Zuo, Ruiyu; Song, Andong; Zheng, Qiuhong; Wang, Ping; Wang, Xiao; Liu, Junxi

2012-01-01

In order to increase nutrient values of corn stover, effects of steam explosion (2.5 MPa, 200 s) and Aspergillus oryzae (A. oryzae) fermentation on cellulose and lignin degradation were studied. The results showed the contents of cellulose, hemicellulose and lignin in the exploded corn stover were 8.47%, 50.45% and 36.65% lower than that in the untreated one, respectively (P<0.05). The contents of cellulose and hemicellulose in the exploded and fermented corn stover (EFCS) were decreased by 24.36% and 69.90%, compared with the untreated one (P<0.05); decreased by 17.35% and 38.59%, compared with the exploded one (P<0.05). The scanning electron microscope observations demonstrated that the combined steam explosion and fermentation destructed corn stover. The activities of enzymes in EFCS were increased. The metabolic experiment showed that about 8% EFCS could be used to replace corn meal in broiler diets, which made EFCS become animal feedstuff possible. Copyright © 2011 Elsevier Ltd. All rights reserved.

Corn grain yield response to stover removal under variable nitrogen, irrigation, and carbon amendments

USDA-ARS?s Scientific Manuscript database

Demand for corn (Zea mays L.) stover either for livestock or cellulosic ethanol production have increased the importance of determining stover removal effects on biomass production. The objectives of this study was to evaluate yield response and N use from continuous stover removal under two irriga...

Comparative studies on thermochemical characterization of corn stover pretreated by white-rot and brown-rot fungi.

PubMed

Zeng, Yelin; Yang, Xuewei; Yu, Hongbo; Zhang, Xiaoyu; Ma, Fuying

2011-09-28

The effects of white-rot and brown-rot fungal pretreatment on the chemical composition and thermochemical conversion of corn stover were investigated. Fungus-pretreated corn stover was analyzed by Fourier transform infrared spectroscopy and X-ray diffraction analysis to characterize the changes in chemical composition. Differences in thermochemical conversion of corn stover after fungal pretreatment were investigated using thermogravimetric and pyrolysis analysis. The results indicated that the white-rot fungus Irpex lacteus CD2 has great lignin-degrading ability, whereas the brown-rot fungus Fomitopsis sp. IMER2 preferentially degrades the amorphous regions of the cellulose. The biopretreatment favors thermal decomposition of corn stover. The weight loss of IMER2-treated acid detergent fiber became greater, and the oil yield increased from 32.7 to 50.8%. After CD2 biopretreatment, 58% weight loss of acid detergent lignin was achieved and the oil yield increased from 16.8 to 26.8%.

40 CFR 180.438 - Lambda-cyhalothrin and an isomer gamma-cyhalothrin; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Corn, pop, grain 0.05 Corn, pop, stover 1.0 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with..., seed 1.0 Cattle, fat 3.0 Cattle, meat 0.2 Cattle, meat byproducts 0.2 Corn, field, flour 0.15 Corn, field, forage 6.0 Corn, field, grain 0.05 Corn, field, stover 1.0 Corn, pop, grain 0.05 Corn, pop, grain...

40 CFR 180.438 - Lambda-cyhalothrin and an isomer gamma-cyhalothrin; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Corn, pop, grain 0.05 Corn, pop, stover 1.0 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with..., seed 1.0 Cattle, fat 3.0 Cattle, meat 0.2 Cattle, meat byproducts 0.2 Corn, field, flour 0.15 Corn, field, forage 6.0 Corn, field, grain 0.05 Corn, field, stover 1.0 Corn, pop, grain 0.05 Corn, pop, grain...

40 CFR 180.438 - Lambda-cyhalothrin and an isomer gamma-cyhalothrin; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Corn, pop, grain 0.05 Corn, pop, stover 1.0 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with..., seed 1.0 Cattle, fat 3.0 Cattle, meat 0.2 Cattle, meat byproducts 0.2 Corn, field, flour 0.15 Corn, field, forage 6.0 Corn, field, grain 0.05 Corn, field, stover 1.0 Corn, pop, grain 0.05 Corn, pop, grain...

Ethanol production via simultaneous saccharification and fermentation of sodium hydroxide treated corn stover using Phanerochaete chrysosporium and Gloeophyllum trabeum.

PubMed

Vincent, Micky; Pometto, Anthony L; van Leeuwen, J Hans

2014-04-01

Ethanol was produced via the simultaneous saccharification and fermentation (SSF) of dilute sodium hydroxide treated corn stover. Saccharification was achieved by cultivating either Phanerochaete chrysosporium or Gloeophyllum trabeum on the treated stover, and fermentation was then performed by using either Saccharomyces cerevisiae or Escherichia coli K011. Ethanol production was highest on day 3 for the combination of G. trabeum and E. coli K011 at 6.68 g/100g stover, followed by the combination of P. chrysosporium and E. coli K011 at 5.00 g/100g stover. SSF with S. cerevisiae had lower ethanol yields, ranging between 2.88 g/100g stover at day 3 (P. chrysosporium treated stover) and 3.09 g/100g stover at day 4 (G. trabeum treated stover). The results indicated that mild alkaline pretreatment coupled with fungal saccharification offers a promising bioprocess for ethanol production from corn stover without the addition of commercial enzymes. Published by Elsevier Ltd.

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

PubMed Central

2014-01-01

Background In a biorefinery producing cellulosic biofuels, biomass pretreatment will significantly influence the efficacy of enzymatic hydrolysis and microbial fermentation. Comparison of different biomass pretreatment techniques by studying the impact of pretreatment on downstream operations at industrially relevant conditions and performing comprehensive mass balances will help focus attention on necessary process improvements, and thereby help reduce the cost of biofuel production. Results An on-going collaboration between the three US Department of Energy (DOE) funded bioenergy research centers (Great Lakes Bioenergy Research Center (GLBRC), Joint BioEnergy Institute (JBEI) and BioEnergy Science Center (BESC)) has given us a unique opportunity to compare the performance of three pretreatment processes, notably dilute acid (DA), ionic liquid (IL) and ammonia fiber expansion (AFEXTM), using the same source of corn stover. Separate hydrolysis and fermentation (SHF) was carried out using various combinations of commercially available enzymes and engineered yeast (Saccharomyces cerevisiae 424A) strain. The optimal commercial enzyme combination (Ctec2: Htec2: Multifect Pectinase, percentage total protein loading basis) was evaluated for each pretreatment with a microplate-based assay using milled pretreated solids at 0.2% glucan loading and 15 mg total protein loading/g of glucan. The best enzyme combinations were 67:33:0 for DA, 39:33:28 for IL and 67:17:17 for AFEX. The amounts of sugar (kg) (glucose: xylose: total gluco- and xylo-oligomers) per 100 kg of untreated corn stover produced after 72 hours of 6% glucan loading enzymatic hydrolysis were: DA (25:2:2), IL (31:15:2) and AFEX (26:13:7). Additionally, the amounts of ethanol (kg) produced per 100 kg of untreated corn stover and the respective ethanol metabolic yield (%) achieved with exogenous nutrient supplemented fermentations were: DA (14.0, 92.0%), IL (21.2, 93.0%) and AFEX (20.5, 95.0%), respectively. 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

Process integration for simultaneous saccharification, fermentation, and recovery (SSFR): Production of butanol from corn stover using Clostridium beijerinckii P260

USDA-ARS?s Scientific Manuscript database

A simultaneous saccharification, fermentation, and recovery (SSFR) process was developed for production of acetone butanol ethanol (AB or ABE), of which butanol is the main product, from corn stover employing Clostridium beijerinckii P260. Of the 86 gL^-1^ corn stover, over 97% of the sugars were r...

Effects of irrigation, cover crop, and manure on soil greenhouse gas emissions after stover removal in no-till continuous corn

USDA-ARS?s Scientific Manuscript database

Corn stover is used widely for livestock co-feed and is targeted as a near-term feedstock for the developing cellulosic ethanol industry. High biomass production in intensely managed systems, such as irrigated continuous corn, may have a greater potential to provide stover for either livestock or bi...

40 CFR 180.579 - Fenamidone; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... of application of fenamidone to the crops in paragraph (a)(1). Commodity Parts per million Corn, field, forage 0.25 Corn, field, grain 0.02 Corn, field, stover 0.40 Corn, sweet, forage 0.15 Corn, sweet, kernel plus cob with husks removed 0.02 Corn, sweet, stover 0.20 Soybean, forage 0.15 Soybean, hay 0.25...

Ball milling pretreatment of corn stover for enhancing the efficiency of enzymatic hydrolysis.

PubMed

Lin, Zengxiang; Huang, He; Zhang, Hongman; Zhang, Lin; Yan, Lishi; Chen, Jingwen

2010-11-01

Ethanol can be produced from lignocellulosic biomass with the usage of ball milling pretreatment followed by enzymatic hydrolysis and fermentation. The sugar yields from lignocellulosic feed stocks are critical parameters for ethanol production process. The research results from this paper indicated that the yields of glucose and xylose were improved by adding any of the following dilute chemical reagents: H(2)SO(4), HCl, HNO(3), CH(3)COOH, HCOOH, H(3)PO(4), and NaOH, KOH, Ca(OH)(2), NH(3)·H(2)O in the ball milling pretreatment of corn stover. The optimal enzymatic hydrolysis efficiencies were obtained under the conditions of ball milling in the alkali medium that was due to delignification. The data also demonstrated that ball milling pretreatment was a robust process. From the microscope image of ball milling-pretreated corn stover, it could be observed that the particle size of material was decreased and the fiber structure was more loosely organized. Meanwhile, the results indicate that the treatment effect of wet milling is better than that of dry milling. The optimum parameters for the milling process were ball speed of 350 r/min, solid/liquid ratio of 1:10, raw material particle size with 0.5 mm, and number of balls of 20 (steel ball, Φ = 10 mm), grinding for 30 min. In comparison with water milling process, alkaline milling treatment could increase the enzymatic hydrolysis efficiency of corn stover by 110%; and through the digestion process with the combination of xylanase and cellulase mixture, the hydrolysis efficiency could increase by 160%.

Biological abatement of cellulase inhibitors

USDA-ARS?s Scientific Manuscript database

Bio-abatement uses a fungus to metabolize and remove fermentation inhibitors. To determine whether bio-abatement could alleviate enzyme inhibitor effects observed in biomass liquors after pretreatment, corn stover at 10% (w/v) solids was pretreated with either dilute acid or liquid hot water. The ...

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. Copyright © 2013 Elsevier Ltd. All rights reserved.

Comparing the fermentation performance of Escherichia coli KO11, Saccharomyces cerevisiae 424A(LNH-ST) and Zymomonas mobilis AX101 for cellulosic ethanol production

PubMed Central

2010-01-01

Background Fermentations using Escherichia coli KO11, Saccharomyces cerevisiae 424A(LNH-ST), and Zymomonas mobilis AX101 are compared side-by-side on corn steep liquor (CSL) media and the water extract and enzymatic hydrolysate from ammonia fiber expansion (AFEX)-pretreated corn stover. Results The three ethanologens are able produce ethanol from a CSL-supplemented co-fermentation at a metabolic yield, final concentration and rate greater than 0.42 g/g consumed sugars, 40 g/L and 0.7 g/L/h (0-48 h), respectively. Xylose-only fermentation of the tested ethanologenic bacteria are five to eight times faster than 424A(LNH-ST) in the CSL fermentation. All tested strains grow and co-ferment sugars at 15% w/v solids loading equivalent of ammonia fiber explosion (AFEX)-pretreated corn stover water extract. However, both KO11 and 424A(LNH-ST) exhibit higher growth robustness than AX101. In 18% w/w solids loading lignocellulosic hydrolysate from AFEX pretreatment, complete glucose fermentations can be achieved at a rate greater than 0.77 g/L/h. In contrast to results from fermentation in CSL, S. cerevisiae 424A(LNH-ST) consumed xylose at the greatest extent and rate in the hydrolysate compared to the bacteria tested. Conclusions Our results confirm that glucose fermentations among the tested strains are effective even at high solids loading (18% by weight). However, xylose consumption in the lignocellulosic hydrolysate is the major bottleneck affecting overall yield, titer or rate of the process. In comparison, Saccharomyces cerevisiae 424A(LNH-ST) is the most relevant strains for industrial production for its ability to ferment both glucose and xylose from undetoxified and unsupplemented hydrolysate from AFEX-pretreated corn stover at high yield. PMID:20507563

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

USDA-ARS?s Scientific Manuscript database

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...

[Process strategy for ethanol production from lignocellulose feedstock under extremely low water usage and high solids loading conditions].

PubMed

Zhang, Jian; Chu, Deqiang; Yu, Zhanchun; Zhang, Xiaoxi; Deng, Hongbo; Wang, Xiusheng; Zhu, Zhinan; Zhang, Huaiqing; Dai, Gance; Bao, Jie

2010-07-01

The massive water and steam are consumed in the production of cellulose ethanol, which correspondingly results in the significant increase of energy cost, waster water discharge and production cost as well. In this study, the process strategy under extremely low water usage and high solids loading of corn stover was investigated experimentally and computationally. The novel pretreatment technology with zero waste water discharge was developed; in which a unique biodetoxification method using a kerosene fungus strain Amorphotheca resinae ZN1 to degrade the lignocellulose derived inhibitors was applied. With high solids loading of pretreated corn stover, high ethanol titer was achieved in the simultaneous saccharification and fermentation process, and the scale-up principles were studied. Furthermore, the flowsheet simulation of the whole process was carried out with the Aspen plus based physical database, and the integrated process developed was tested in the biorefinery mini-plant. Finally, the core technologies were applied in the cellulose ethanol demonstration plant, which paved a way for the establishment of an energy saving and environment friendly technology of lignocellulose biotransformation with industry application potential.

Scale-up and process integration of sugar production by acidolysis of municipal solid waste/corn stover blends in ionic liquids

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

Li, Chenlin; Liang, Ling; Sun, Ning

The study presents the successful scale-up demonstration of the acid-assisted IL deconstruction on feedstock blends of municipal solid wastes and agricultural residues (corn stover) by 30-fold, relative to the bench scale (6L vs 0.2L), at 10% solid loading. By integrating IL pretreatment and acid hydrolysis with subsequent centrifugation and extraction, the sugar and lignin products can be further recovered efficiently. This scale-up development at Advanced Biofuels/Bioproducts Process Demonstration Unit (ABPDU) will leverage the opportunity and synergistic efforts towards developing a cost-effective IL based deconstruction technology by drastically eliminating enzyme, reducing water usage, and simplifying the downstream sugar/lignin recovery and ILmore » recycling. Results indicate that MSW blends are viable and valuable resource to consider when assessing biomass availability and affordability for lignocellulosic biorefineries. This scale-up evaluation demonstrates that the acid-assisted IL deconstruction technology can be effectively scaled up to larger operations and the current study established the baseline of scaling parameters for this process.« less

Scale-up and process integration of sugar production by acidolysis of municipal solid waste/corn stover blends in ionic liquids

DOE PAGES

Li, Chenlin; Liang, Ling; Sun, Ning; ...

2017-01-05

The study presents the successful scale-up demonstration of the acid-assisted IL deconstruction on feedstock blends of municipal solid wastes and agricultural residues (corn stover) by 30-fold, relative to the bench scale (6L vs 0.2L), at 10% solid loading. By integrating IL pretreatment and acid hydrolysis with subsequent centrifugation and extraction, the sugar and lignin products can be further recovered efficiently. This scale-up development at Advanced Biofuels/Bioproducts Process Demonstration Unit (ABPDU) will leverage the opportunity and synergistic efforts towards developing a cost-effective IL based deconstruction technology by drastically eliminating enzyme, reducing water usage, and simplifying the downstream sugar/lignin recovery and ILmore » recycling. Results indicate that MSW blends are viable and valuable resource to consider when assessing biomass availability and affordability for lignocellulosic biorefineries. This scale-up evaluation demonstrates that the acid-assisted IL deconstruction technology can be effectively scaled up to larger operations and the current study established the baseline of scaling parameters for this process.« less

40 CFR 180.582 - Pyraclostrobin; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 13-07A 4.0 Canistel 0.6 Citrus, dried pulp 12.5 Citrus, oil 9.0 Coffee, green bean 1 0.3 Corn, field, forage 5.0 Corn, field, grain 0.1 Corn, field, refined oil 0.2 Corn, field, stover 17.0 Corn, pop, grain 0.1 Corn, pop, stover 17.0 Corn, sweet, forage 5.0 Corn, sweet, kernel plus cob with husks removed 0...

40 CFR 180.332 - Metribuzin; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Barley, straw 1.0 Carrot, roots 0.3 Cattle, fat 0.7 Cattle, meat 0.7 Cattle, meat byproducts 0.7 Corn, field, forage 0.1 Corn, field, grain 0.05 Corn, field, stover 0.1 Corn, pop, grain 0.05 Corn, sweet, forage 0.1 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.1 Egg 0.01 Goat...

40 CFR 180.361 - Pendimethalin; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... greens, subgroup 5B 0.20 Carrot 0.5 Citrus, oil 0.5 Corn, field, forage 0.1 Corn, field, grain 0.1 Corn, field, stover 0.1 Corn, pop, grain 0.1 Corn, sweet, forage 0.1 Corn, sweet, kernel plus cob with husks removed 0.1 Corn, sweet, stover 0.1 Cotton, gin byproducts 3.0 Cotton, undelinted seed 0.1 Crayfish 0.05...

40 CFR 180.469 - Dichlormid; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Parts per million Expiration/revocation date Corn, field, forage 0.05 12/31/10 Corn, field, grain 0.05 12/31/10 Corn, field, stover 0.05 12/31/10 Corn, pop, grain 0.05 12/31/10 Corn, pop, stover 0.05 12/31/10 Corn, sweet, forage 0.05 12/31/10 Corn, sweet, kernel plus cob with husks removed 0.05 12/31/10...

40 CFR 180.332 - Metribuzin; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Barley, straw 1.0 Carrot, roots 0.3 Cattle, fat 0.7 Cattle, meat 0.7 Cattle, meat byproducts 0.7 Corn, field, forage 0.1 Corn, field, grain 0.05 Corn, field, stover 0.1 Corn, pop, grain 0.05 Corn, sweet, forage 0.1 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.1 Egg 0.01 Goat...

40 CFR 180.361 - Pendimethalin; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... greens, subgroup 5B 0.20 Carrot 0.5 Citrus, oil 0.5 Corn, field, forage 0.1 Corn, field, grain 0.1 Corn, field, stover 0.1 Corn, pop, grain 0.1 Corn, sweet, forage 0.1 Corn, sweet, kernel plus cob with husks removed 0.1 Corn, sweet, stover 0.1 Cotton, gin byproducts 3.0 Cotton, undelinted seed 0.1 Crayfish 0.05...

40 CFR 180.332 - Metribuzin; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Barley, straw 1.0 Carrot, roots 0.3 Cattle, fat 0.7 Cattle, meat 0.7 Cattle, meat byproducts 0.7 Corn, field, forage 0.1 Corn, field, grain 0.05 Corn, field, stover 0.1 Corn, pop, grain 0.05 Corn, sweet, forage 0.1 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.1 Egg 0.01 Goat...

40 CFR 180.332 - Metribuzin; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Barley, straw 1.0 Carrot, roots 0.3 Cattle, fat 0.7 Cattle, meat 0.7 Cattle, meat byproducts 0.7 Corn, field, forage 0.1 Corn, field, grain 0.05 Corn, field, stover 0.1 Corn, pop, grain 0.05 Corn, sweet, forage 0.1 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.1 Egg 0.01 Goat...

Cellulase retention and sugar removal by membrane ultrafiltration during lignocellulosic biomass hydrolysis.

PubMed

Knutsen, Jeffrey S; Davis, Robert H

2004-01-01

Technologies suitable for the separation and reuse of cellulase enzymes during the enzymatic saccharification of pretreated corn stover are investigated to examine the economic and technical viability of processes that promote cellulase reuse while removing inhibitory reaction products such as glucose and cellobiose. The simplest and most suitable separation is a filter with relatively large pores on the order of 20-25 mm that retains residual corn stover solids while passing reaction products such as glucose and cellobiose to form a sugar stream for a variety of end uses. Such a simple separation is effective because cellulase remains bound to the residual solids. Ultrafiltration using 50-kDa polyethersulfone membranes to recover cellulase enzymes in solution was shown not to enhance further the saccharification rate or overall conversion. Instead, it appears that the necessary cellulase enzymes, including beta-glucosidase, are tightly bound to the substrate; when fresh corn stover is contacted with highly washed residual solids, without the addition of fresh enzymes, glucose is generated at a high rate. When filtration was applied multiple times, the concentration of inhibitory reaction products such as glucose and cellobiose was reduced from 70 to 10 g/L. However, an enhanced saccharification performance was not observed, most likely because the concentration of the inhibitory products remained too high. Further reduction in the product concentration was not investigated, because it would make the reaction unnecessarily complex and result in a product stream that is much too dilute to be useful. Finally, an economic analysis shows that reuse of cellulase can reduce glucose production costs, especially when the enzyme price is high. The most economic performance is shown to occur when the cellulase enzyme is reused and a small amount of fresh enzyme is added after each separation step to replace lost or deactivated enzyme.

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

USDA-ARS?s Scientific Manuscript database

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...

Study on the Effect of cellulolytic strain MYB3 for Corn Stover Fermentation

NASA Astrophysics Data System (ADS)

Yan, Han; Bai, Bing; Cheng, Xiao-Xiao; Li, Guang-Chun; Huang, Shi-Chen; Piao, Chun-Xiang

2018-03-01

The effects of corn stover fermentation with the Bacillus megaterium MYB3 was studied in this paper. The results showed that the decomposition rates of cellulose and hemicellulose were 49.6%, 43.46% after 20 days respectively, after fermentation, pH was changed to 5.68, and adjusted to corn stover initial pH 3 to achieve the purpose of sterilization. The decomposition rate was significantly increased by adding corn flour. After adjusting fermentation composes with the ratio of the corn stove to corn flour was 15 : 1, the decomposition rate of cellulose would be 52.37% for 10 days.

40 CFR 180.473 - Glufosinate ammonium; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 1.1 Canola, seed 0.40 Cattle, fat 0.40 Cattle, meat 0.15 Cattle, meat byproducts 6.0 Corn, field forage 4.0 Corn, field, grain 0.20 Corn, field, stover 6.0 Corn, sweet, forage 1.5 Corn, sweet, kernels plus cob with husks removed 0.30 Corn, sweet, stover 6.0 Cotton, gin byproducts 15 Cotton, undelinted...

40 CFR 180.368 - Metolachlor; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 0.05 Cattle, meat 0.02 Cattle, meat byproducts, except kidney and liver 0.04 Corn, field, forage 6.0 Corn, field, grain 0.10 Corn, field, stover 6.0 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob..., sweet, kernel plus cob with husks removed 0.10 Corn, sweet, stover 6.0 Cotton, gin byproducts 4.0 Cotton...

40 CFR 180.473 - Glufosinate ammonium; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 1.1 Canola, seed 0.40 Cattle, fat 0.40 Cattle, meat 0.15 Cattle, meat byproducts 6.0 Corn, field forage 4.0 Corn, field, grain 0.20 Corn, field, stover 6.0 Corn, sweet, forage 1.5 Corn, sweet, kernels plus cob with husks removed 0.30 Corn, sweet, stover 6.0 Cotton, gin byproducts 15 Cotton, undelinted...

Rheological modification of corn stover biomass at high solids concentrations

Treesearch

Joseph R. Samaniuk; C. Tim Scott; Thatcher W. Root; Daniel J. Klingenberg

2012-01-01

Additives were tested for their ability to modify the rheology of lignocellulosic biomass. Additive types included water-soluble polymers (WSPs), surfactants, and fine particles. WSPs were the most effective rheological modifiers, reducing yield stresses of concentrated biomass by 60–80% for additive concentrations of 1–2 wt. % (based on mass of dry biomass solids)....

Rheology of concentrated biomass

Treesearch

J.R. Samaniuk; J. Wang; T.W. Root; C.T. Scott; D.J. Klingenberg

2011-01-01

Economic processing of lignocellulosic biomass requires handling the biomass at high solids concentration. This creates challenges because concentrated biomass behaves as a Bingham-like material with large yield stresses. Here we employ torque rheometry to measure the rheological properties of concentrated lignocellulosic biomass (corn stover). Yield stresses obtained...

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

PubMed

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

2017-08-01

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

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

PubMed

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

2016-04-01

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

Lower pressure heating steam is practical for the distributed dry dilute sulfuric acid pretreatment.

PubMed

Shao, Shuai; Zhang, Jian; Hou, Weiliang; Qureshi, Abdul Sattar; Bao, Jie

2017-08-01

Most studies paid more attention to the pretreatment temperature and the resulted pretreatment efficiency, while ignored the heating media and their scalability to an industry scale. This study aimed to use a relative low pressure heating steam easily provided by steam boiler to meet the requirement of distributed dry dilute acid pretreatment. The results showed that the physical properties of the pretreated corn stover were maintained stable using the steam pressure varying from 1.5, 1.7, 1.9 to 2.1MPa. Enzymatic hydrolysis and high solids loading simultaneous saccharification and fermentation (SSF) results were also satisfying. CFD simulation indicated that the high injection velocity of the low pressure steam resulted in a high steam holdup and made the mixing time of steam and solid corn stover during pretreatment much shorter in comparison with the higher pressure steam. This study provides a design basis for the boiler requirement in distributed pretreatment concept. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed

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

2017-11-01

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

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

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

Qin, Zhangcai; Canter, Christina E.; Dunn, Jennifer B.

Land management practices such as cover crop adoption or manure application that can increase soil organic carbon (SOC) may provide a way to counter SOC loss upon removal of stover from corn fields for use as a biofuel feedstock. This report documents the data, methodology, and assumptions behind the incorporation of land management practices into corn-soybean systems that dominate U.S. grain production using varying levels of stover removal in the GREETTM (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) model and its CCLUB (Carbon Calculator for Land Use change from Biofuels production) module. Tillage (i.e., conventional, reduced and nomore » tillage), corn stover removal (i.e., at 0, 30% and 60% removal rate), and organic matter input techniques (i.e., cover crop and manure application) are included in the analysis as major land management practices. Soil carbon changes associated with land management changes were modeled with a surrogate CENTURY model. The resulting SOC changes were incorporated into CCLUB while GREET was expanded to include energy and material consumption associated with cover crop adoption and manure application. Life-cycle greenhouse gas (GHG) emissions of stover ethanol were estimated using a marginal approach (all burdens and benefits assigned to corn stover ethanol) and an energy allocation approach (burdens and benefits divided between grain and stover ethanol). In the latter case, we considered corn grain and corn stover ethanol to be produced at an integrated facility. Life-cycle GHG emissions of corn stover ethanol are dependent upon the analysis approach selected (marginal versus allocation) and the land management techniques applied. The expansion of CCLUB and GREET to accommodate land management techniques can produce a wide range of results because users can select from multiple scenario options such as choosing tillage levels, stover removal rates, and whether crop yields increase annually or remain constant. In a scenario with conventional tillage and a 30% stover removal rate, life-cycle GHG emissions for a combined gallon of corn grain and stover ethanol without cover crop adoption or manure application are 49 g CO2eq MJ-1, in comparison with 91 g CO2eq MJ-1 for petroleum gasoline. Adopting a cover crop or applying manure reduces the former ethanol life-cycle GHG emissions by 8% and 10%, respectively. We considered two different life cycle analysis approaches to develop estimates of life-cycle GHG emissions for corn stover ethanol, marginal analysis and energy allocation. In the same scenario, this fuel has GHG emissions of 12 – 20 g CO2eq MJ-1 (for manure and cover crop application, respectively) and 45 – 48 g CO2eq MJ-1 with the marginal approach and the energy allocation approach, respectively.« less

Life-cycle analysis of bio-based aviation fuels.

PubMed

Han, Jeongwoo; Elgowainy, Amgad; Cai, Hao; Wang, Michael Q

2013-12-01

Well-to-wake (WTWa) analysis of bio-based aviation fuels, including hydroprocessed renewable jet (HRJ) from various oil seeds, Fischer-Tropsch jet (FTJ) from corn-stover and co-feeding of coal and corn-stover, and pyrolysis jet from corn stover, is conducted and compared with petroleum jet. WTWa GHG emission reductions relative to petroleum jet can be 41-63% for HRJ, 68-76% for pyrolysis jet and 89% for FTJ from corn stover. The HRJ production stage dominates WTWa GHG emissions from HRJ pathways. The differences in GHG emissions from HRJ production stage among considered feedstocks are much smaller than those from fertilizer use and N2O emissions related to feedstock collection stage. Sensitivity analyses on FTJ production from coal and corn-stover are also conducted, showing the importance of biomass share in the feedstock, carbon capture and sequestration options, and overall efficiency. For both HRJ and FTJ, co-product handling methods have significant impacts on WTWa results. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

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

Amber N. Hoover; Jaya Shankar Tumuluru; Farzaneh Teymouri

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 ormore » 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.« less

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.

Enhanced furfural production from raw corn stover employing a novel heterogeneous acid catalyst.

PubMed

Li, Wenzhi; Zhu, Yuanshuai; Lu, Yijuan; Liu, Qiyu; Guan, Shennan; Chang, Hou-Min; Jameel, Hasan; Ma, Longlong

2017-12-01

With the aim to enhance the direct conversion of raw corn stover into furfural, a promising approach was proposed employing a novel heterogeneous strong acid catalyst (SC-CaC t -700) in different solvents. The novel catalyst was characterized by elemental analysis, N 2 adsorption-desorption, FT-IR, XPS, TEM and SEM. The developed catalytic system demonstrated superior efficacy for furfural production from raw corn stover. The effects of reaction temperature, residence time, catalyst loading, substrate concentration and solvent were investigated and optimized. 93% furfural yield was obtained from 150mg corn stover at 200°C in 100min using 45mg catalyst in γ-valerolactone (GVL). In comparison, 51.5% furfural yield was achieved in aqueous media under the same conditions (200°C, 5h, and 45mg catalyst), which is of great industrial interest. Furfural was obtained from both hemicelluloses and cellulose in corn stover, which demonstrated a promising routine to make the full use of biomass. Copyright © 2017 Elsevier Ltd. All rights reserved.

40 CFR 180.232 - Butylate; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Expiration/Revocation Date Corn, field, forage 0.1 3/23/13 Corn, field, grain 0.1 3/23/13 Corn, field, stover 0.1 3/23/13 Corn, pop, grain 0.1 3/23/13 Corn, pop, stover 0.1 3/23/13 Corn, sweet, forage 0.1 3/23/13 Corn, sweet, kernel plus cob with husks removed 0.1 3/23/13 (b) Section 18 emergency exemptions...

40 CFR 180.232 - Butylate; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Expiration/revocation date Corn, field, forage 0.1 3/23/13 Corn, field, grain 0.1 3/23/13 Corn, field, stover 0.1 3/23/13 Corn, pop, grain 0.1 3/23/13 Corn, pop, stover 0.1 3/23/13 Corn, sweet, forage 0.1 3/23/13 Corn, sweet, kernel plus cob with husks removed 0.1 3/23/13 (b) Section 18 emergency exemptions...

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

DOE PAGES

Ren, Lantian; Cafferty, Kara; Roni, Mohammad; ...

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

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

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

Sokhansanj, Shahabaddine; Mani, Sudhagar; Togore, Sam

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,more » 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.« less

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

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

Ren, Lantian; Cafferty, Kara; Roni, Mohammad

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

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

DOE PAGES

Bhagavatula, Abhijit; Huffman, Gerald; Shah, Naresh; ...

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

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

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

Bhagavatula, Abhijit; Huffman, Gerald; Shah, Naresh

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

40 CFR 180.535 - Fluroxypyr 1-methylheptyl ester; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

....0 Cattle, fat 0.1 Cattle, kidney 1.5 Cattle, meat 0.1 Cattle, meat byproducts 0.1 Corn, field, forage 1.0 Corn, field, grain 0.02 Corn, field, stover 0.5 Corn, sweet, forage 1.0 Corn, sweet, kernel plus cob with husks removed 0.02 Corn, sweet, stover 2.0 Fruit, pome, group 11 0.02 Garlic, bulb 0.03...

40 CFR 180.555 - Trifloxystrobin; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... plus cob with husks removed 0.04 Corn, sweet, stover 4.0 Egg 0.04 Fruit, citrus, group 10 0.6 Fruit... Cattle, meat byproducts 0.1 Citrus, dried pulp 1.0 Citrus, oil 38 Coffee, green bean 2 0.02 Corn, field, forage 6.0 Corn, field, grain 0.05 Corn, field, stover 7 Corn, field, refined oil 0.1 Corn, pop, grain 0...

40 CFR 180.535 - Fluroxypyr 1-methylheptyl ester; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

....0 Cattle, fat 0.1 Cattle, kidney 1.5 Cattle, meat 0.1 Cattle, meat byproducts 0.1 Corn, field, forage 1.0 Corn, field, grain 0.02 Corn, field, stover 0.5 Corn, sweet, forage 1.0 Corn, sweet, kernel plus cob with husks removed 0.02 Corn, sweet, stover 2.0 Fruit, pome, group 11 0.02 Garlic, bulb 0.03...

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

USDA-ARS?s Scientific Manuscript database

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

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

DOE PAGES

Han, Jeongwoo; Tao, Ling; Wang, Michael

2017-01-24

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

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

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

Han, Jeongwoo; Tao, Ling; Wang, Michael

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

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

PubMed

Han, Jeongwoo; Tao, Ling; Wang, Michael

2017-01-01

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

Liquefaction of corn stover and preparation of polyester from the liquefied polyol.

PubMed

Yu, Fei; Liu, Yuhuan; Pan, Xuejun; Lin, Xiangyang; Liu, Chengmei; Chen, Paul; Ruan, Roger

2006-01-01

This research investigated a novel process to prepare polyester from corn stover through liquefaction and crosslinking processes. First, corn stover was liquefied in organic solvents (90 wt% ethylene glycol and 10 wt% ethylene carbonate) with catalysts at moderate temperature under atmospheric pressure. The effect of liquefaction temperature, biomass content, and type of catalyst, such as H2SO4, HCl, H3PO4, and ZnCl2, was evaluated. Higher liquefaction yield was achieved in 2 wt% sulfuric acid, 1/4 (w/w) stover to liquefying reagent ratio; 160 degrees C temperature, in 2 h. The liquefied corn stover was rich in polyols, which can be directly used as feedstock for making polymers without further separation or purification. Second, polyester was made from the liquefied corn stover by crosslinking with multifunctional carboxylic acids and/or cyclic acid anhydrides. The tensile strength of polyester is about 5 MPa and the elongation is around 35%. The polyester is stable in cold water and organic solvents and readily biodegradable as indicated by 82% weight loss when buried in damp soil for 10 mo. The results indicate that this novel polyester could be used for the biodegradable garden mulch film production.

Ling Tao, Ph.D. | NREL

Science.gov Websites

| 303-384-7809 Orcid ID http://orcid.org/0000-0003-1063-1984 Research Interests Techno-economic analysis ) with Corn Stover using Response Surface Methodology (RSM) and Techno Economic Analysis (TEA)," ; Biotechnology for Biofuels (2014) "Performance and techno-economic assessment of several solid-liquid

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

USDA-ARS?s Scientific Manuscript database

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...

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

USDA-ARS?s Scientific Manuscript database

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 ...

Inclusion of calcium hydroxide-treated corn stover as a partial forage replacement in diets for lactating dairy cows.

PubMed

Casperson, Brittany A; Wertz-Lutz, Aimee E; Dunn, Jim L; Donkin, Shawn S

2018-03-01

Chemical treatment may improve the nutritional value of corn crop residues, commonly referred to as corn stover, and the potential use of this feed resource for ruminants, including lactating dairy cows. The objective of this study was to determine the effect of prestorage chopping, hydration, and treatment of corn stover with Ca(OH) 2 on the feeding value for milk production, milk composition, and dry matter intake (DMI). Multiparous mid-lactation Holstein cows (n = 30) were stratified by parity and milk production and randomly assigned to 1 of 3 diets. Corn stover was chopped, hydrated, and treated with 6% Ca(OH) 2 (as-fed basis) and stored in horizontal silo bags. Cows received a control (CON) total mixed ration (TMR) or a TMR in which a mixture of treated corn stover and distillers grains replaced either alfalfa haylage (AHsub) or alfalfa haylage and an additional portion of corn silage (AH+CSsub). Treated corn stover was fed in a TMR at 0, 15, and 30% of the diet DM for the CON, AHsub, and AH+CSsub diets, respectively. Cows were individually fed in tiestalls for 10 wk. Milk production was not altered by treatment. Compared with the CON diet, DMI was reduced when the AHsub diet was fed and tended to be reduced when cows were fed the AH+CSsub diet (25.9, 22.7, and 23.1 ± 0.88 kg/d for CON, AHsub, and AH+CSsub diets, respectively). Energy-corrected milk production per unit of DMI (kg/kg) tended to increase with treated corn stover feeding. Milk composition, energy-corrected milk production, and energy-corrected milk per unit of DMI (kg/kg) were not different among treatments for the 10-wk feeding period. Cows fed the AHsub and AH+CSsub diets had consistent DMI over the 10-wk treatment period, whereas DMI for cows fed the CON diet increased slightly over time. Milk production was not affected by the duration of feeding. These data indicate that corn stover processing, prestorage hydration, and treatment with calcium hydroxide can serve as an alternative to traditional haycrop and corn silage in diets fed to mid-lactation dairy cows. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

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

DOE PAGES

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

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

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

Maung, Thein A.; Gustafson, Cole R.

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

Flowability parameters for chopped switchgrass, wheat straw and corn stover

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

Chevanan, Nehru; Womac, A.R.; Bitra, V.S.P.

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 formore » 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.« less

40 CFR 180.242 - Thiabendazole; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., dry, seed 0.1 None Beet, sugar, dried pulp 3.5 12/25/10 Beet, sugar, roots 0.25 12/25/10 Beet, sugar..., forage 0.01 None Corn, pop, grain 0.01 None Corn, pop, stover 0.01 None Corn, sweet, forage 0.01 None Corn, sweet, kernels plus cop with husks removed 0.01 None Corn, sweet, stover 0.01 None Fruit, citrus...

40 CFR 180.242 - Thiabendazole; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., dry, seed 0.1 None Beet, sugar, dried pulp 3.5 12/25/10 Beet, sugar, roots 0.25 12/25/10 Beet, sugar..., forage 0.01 None Corn, pop, grain 0.01 None Corn, pop, stover 0.01 None Corn, sweet, forage 0.01 None Corn, sweet, kernels plus cop with husks removed 0.01 None Corn, sweet, stover 0.01 None Fruit, citrus...

40 CFR 180.242 - Thiabendazole; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., dry, seed 0.1 None Beet, sugar, dried pulp 3.5 12/25/10 Beet, sugar, roots 0.25 12/25/10 Beet, sugar..., forage 0.01 None Corn, pop, grain 0.01 None Corn, pop, stover 0.01 None Corn, sweet, forage 0.01 None Corn, sweet, kernels plus cop with husks removed 0.01 None Corn, sweet, stover 0.01 None Fruit, citrus...

40 CFR 180.242 - Thiabendazole; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., dry, seed 0.1 None Beet, sugar, dried pulp 3.5 12/25/10 Beet, sugar, roots 0.25 12/25/10 Beet, sugar..., forage 0.01 None Corn, pop, grain 0.01 None Corn, pop, stover 0.01 None Corn, sweet, forage 0.01 None Corn, sweet, kernels plus cop with husks removed 0.01 None Corn, sweet, stover 0.01 None Fruit, citrus...

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

DOE PAGES

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

2015-08-18

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

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

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

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

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

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. Copyright 2009 Elsevier Ltd. All rights reserved.

Novel DDR Processing of Corn Stover Achieves High Monomeric Sugar Concentrations from Enzymatic Hydrolysis (230 g/L) and High Ethanol Concentration (10% v/v) During Fermentation

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

Chen, Xiaowen; Jennings, Ed; Shekiro, Joe

Distilling and purifying ethanol, butanol, and other products from second and later generation lignocellulosic biorefineries adds significant capital and operating cost for biofuels production. The energy costs associated with distillation affects plant gate and life cycle analysis costs. Lower titers in fermentation due to lower sugar concentrations from pretreatment increase both energy and production costs. In addition, higher titers decrease the volumes required for enzymatic hydrolysis and fermentation vessels. Therefore, increasing biofuels titers has been a research focus in renewable biofuels production for several decades. In this work, we achieved over 200 g/L of monomeric sugars after high solids enzymaticmore » hydrolysis using the novel deacetylation and disc refining (DDR) process on corn stover. The high sugar concentrations and low chemical inhibitor concentrations from the DDR process allowed ethanol titers as high as 82 g/L in 22 hours, which translates into approximately 10 vol% ethanol. To our knowledge, this is the first time that 10 vol% ethanol in fermentation derived from corn stover without any sugar concentration or purification steps has been reported. Techno-economic analysis shows the higher titer ethanol achieved from the DDR process could significantly reduce the minimum ethanol selling price from cellulosic biomass.« less

Hydrolyzabilities of different corn stover fractions after aqueous ammonia pretreatment.

PubMed

Sun, Zongping; Ge, Xiaoyan; Xin, Donglin; Zhang, Junhua

2014-02-01

The effect of aqueous ammonia pretreatment on the hydrolysis of different corn stover fractions (rind, husk, leaf, and pith) by xylanase (XYL) with cellulases (CELs) was evaluated. The aqueous ammonia pretreatment had excellent delignification ability (above 66%) for different corn stover fractions. The corn rind exhibited the lowest susceptibility to aqueous ammonia pretreatment. The pretreated rind showed the lowest hydrolyzability by CEL and XYL, which was supported by a high content of crystalline cellulose in the hydrolyzed residues of rind, as confirmed by X-ray diffraction (XRD). With the addition of 1 mg XYL/g dry matter, a high glucose yield (above 90%) could be obtained from the pretreated rind by CEL. The results revealed that a high hydrolyzate yield of corn rind after aqueous ammonia pretreatment could be obtained with 1 mg xylanase/g dry matter, showing that aqueous ammonia pretreatment and xylanase addition to cellulases have great potential for the efficient hydrolysis of corn stover without previous fractionation.

40 CFR 180.368 - Metolachlor; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., forage 6.0 Corn, sweet, kernel plus cob with husks removed 0.10 Corn, sweet, stover 6.0 Cotton, gin..., sweet, kernel plus cob with husks removed 0.10 Corn, sweet, stover 40 Cotton, gin byproducts 4.0 Cotton... 0.05 Cattle, meat 0.02 Cattle, meat byproducts, except kidney and liver 0.04 Corn, field, forage 6.0...

40 CFR 180.527 - Flufenacet, N-(4-fluorophenyl)-N-(1-methylethyl)-2-[[5-(trifluoromethyl)-1, 3, 4-thiadiazol-2-yl...

Code of Federal Regulations, 2012 CFR

2012-07-01

... benzenamine moiety in or on the following commodities. Commodity Parts per million Cattle, kidney 0.05 Corn, field, forage 0.4 Corn, field, grain 0.05 Corn, field, stover 0.4 Corn, sweet, forage 0.45 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.30 Goat, kidney 0.05 Hog, kidney 0.05 Horse...

40 CFR 180.527 - Flufenacet, N-(4-fluorophenyl)-N-(1-methylethyl)-2-[[5-(trifluoromethyl)-1, 3, 4-thiadiazol-2-yl...

Code of Federal Regulations, 2014 CFR

2014-07-01

... benzenamine moiety in or on the following commodities. Commodity Parts per million Cattle, kidney 0.05 Corn, field, forage 0.4 Corn, field, grain 0.05 Corn, field, stover 0.4 Corn, sweet, forage 0.45 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.30 Goat, kidney 0.05 Hog, kidney 0.05 Horse...

40 CFR 180.527 - Flufenacet, N-(4-fluorophenyl)-N-(1-methylethyl)-2-[[5-(trifluoromethyl)-1, 3, 4-thiadiazol-2-yl...

Code of Federal Regulations, 2013 CFR

2013-07-01

... benzenamine moiety in or on the following commodities. Commodity Parts per million Cattle, kidney 0.05 Corn, field, forage 0.4 Corn, field, grain 0.05 Corn, field, stover 0.4 Corn, sweet, forage 0.45 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 0.30 Goat, kidney 0.05 Hog, kidney 0.05 Horse...

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Assesment of PM2.5 emission from corn stover burning determining in chamber combustion

NASA Astrophysics Data System (ADS)

Hafidawati; Lestari, P.; Sofyan, A.

2018-04-01

Chamber measurement were conducted to determine Particulate Matter (PM2.5) emission from open burning of corn straw at Garut District, West Java. The of this study is to estimate the concentration of PM2.5 for two types of corn (corncobs and cornstover) for five varieties (Bisma, P29, NK, Bisma, NW). Corn residues were collected and then burned in the chamber combustion. The chamber was designed to simulate the burning in the field, which was observed in the field experiment that meteorological condition was calm wind. The samples were collected using a minivol air sampler. The assessment results of PM2.5 concentrations (mg/m3) from open burning experiment in the chamber for five varieties of corn cobs (Bisma, P29, NK, Bisi, NW) was 9.187; 2.843; 7.409; 3.781; 1.895 respectively. Concentration for corn stover burn was 2.060; 5.283; 4.048; 5.306 and 5.697 respectively. Fluctuations in the value of concentration among these varieties reflect variations in combustion conditions (combustion efficiency) and other parameters including water content, biomass conditions and the meteorological conditions. The combustion efficiency (MCE) of the combustion chamber simulation of corncobs ia lower than the MCE of corn stover, that the concentration PM2.5 more emitted from the burning of corn stover. The results of this study presented provide useful information for the development of local emission factors for PM2.5 from open burning of corn stover in Indonesia.

Comparing corn stover and switchgrass biochar: characterization and sorption properties

USDA-ARS?s Scientific Manuscript database

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...

40 CFR 180.452 - Primisulfuron-methyl; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., fat 0.10 Cattle, meat 0.10 Cattle, meat byproducts 0.10 Corn, field, forage 0.10 Corn, field, grain 0.02 Corn, field, stover 0.10 Corn, pop, grain 0.02 Corn, pop, stover 0.10 Egg 0.10 Goat, fat 0.10 Goat, meat 0.10 Goat, meat byproducts 0.10 Hog, fat 0.10 Hog, meat 0.10 Hog, meat byproducts 0.10 Horse, fat...

40 CFR 180.452 - Primisulfuron-methyl; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., fat 0.10 Cattle, meat 0.10 Cattle, meat byproducts 0.10 Corn, field, forage 0.10 Corn, field, grain 0.02 Corn, field, stover 0.10 Corn, pop, grain 0.02 Corn, pop, stover 0.10 Egg 0.10 Goat, fat 0.10 Goat, meat 0.10 Goat, meat byproducts 0.10 Hog, fat 0.10 Hog, meat 0.10 Hog, meat byproducts 0.10 Horse, fat...

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

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

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.

Direct measures of mechanical energy for knife mill size reduction of switchgrass, wheat straw, and corn stover.

PubMed

Bitra, Venkata S P; Womac, Alvin R; Igathinathane, C; Miu, Petre I; Yang, Yuechuan T; Smith, David R; Chevanan, Nehru; Sokhansanj, Shahab

2009-12-01

Lengthy straw/stalk of biomass may not be directly fed into grinders such as hammer mills and disc refiners. Hence, biomass needs to be preprocessed using coarse grinders like a knife mill to allow for efficient feeding in refiner mills without bridging and choking. 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 knife mill. Direct power inputs were determined for different 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. Overall accuracy of power measurement was calculated to be +/-0.003 kW. Total specific energy (kWh/Mg) was defined as size reduction energy to operate mill with biomass. Effective specific energy was defined as the energy that can be assumed to reach the biomass. The difference is parasitic or no-load energy of mill. Total specific energy for switchgrass, wheat straw, and corn stover chopping increased with knife mill speed, whereas, effective specific energy decreased marginally for switchgrass and increased for wheat straw and corn stover. Total and effective specific energy decreased with an increase in screen size for all the crops studied. Total specific energy decreased with increase in mass feed rate, but effective specific energy increased for switchgrass and wheat straw, and decreased for corn stover at increased feed rate. For knife mill screen size of 25.4 mm and optimum speed of 250 rpm, optimum feed rates were 7.6, 5.8, and 4.5 kg/min for switchgrass, wheat straw, and corn stover, respectively, and the corresponding total specific energies were 7.57, 10.53, and 8.87 kWh/Mg and effective specific energies were 1.27, 1.50, and 0.24 kWh/Mg for switchgrass, wheat straw, and corn stover, respectively. Energy utilization ratios were calculated as 16.8%, 14.3%, and 2.8% for switchgrass, wheat straw, and corn stover, respectively. These data will be useful for preparing the feed material for subsequent fine grinding operations and designing new mills.

40 CFR 180.368 - Metolachlor; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., forage 6.0 Corn, sweet, kernel plus cob with husks removed 0.10 Corn, sweet, stover 6.0 Cotton, gin..., sweet, kernel plus cob with husks removed 0.10 Corn, sweet, stover 6.0 Cotton, gin byproducts 4.0 Cotton... 0.05 Cattle, meat 0.02 Cattle, meat byproducts, except kidney and liver 0.04 Corn, field, forage 6.0...

Stover removal effects on continuous corn yield and nitrogen use efficiency under irrigation

USDA-ARS?s Scientific Manuscript database

Corn (Zea mays L.) residue or stover is harvested as supplemental feed for livestock and is a primary feedstock for cellulosic biofuels. Limited information is available on corn residue removal effects on grain yield under different nitrogen (N) fertilizer rates, irrigation rates and amelioration pr...

Distribution of structural carbohydrates in corn plants across the southeastern USA

USDA-ARS?s Scientific Manuscript database

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...

Soil carbon and nitrogen dynamic after corn stover harvest

USDA-ARS?s Scientific Manuscript database

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...

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. Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.

Estimating the required logistical resources to support the development of a sustainable corn stover bioeconomy in the USA

DOE PAGES

Ebadian, Mahmood; Sokhansanj, Shahabaddine; Webb, Erin

2016-11-23

In this paper, the logistical resources required to develop a bioeconomy based on corn stover in the USA are quantified, including field equipment, storage sites, transportation and handling equipment, workforce, corn growers, and corn lands. These resources are essential to mobilize large quantities of corn stover from corn fields to biorefineries. The logistical resources are estimated over the lifetime of the biorefineries. Seventeen corn-growing states are considered for the logistical resource assessment. Over 6.8 billion gallons of cellulosic ethanol can be produced annually from 108 million dry tons of corn stover in these states. The maximum number of required fieldmore » equipment (i.e., choppers, balers, collectors, loaders, and tractors) is estimated to be 194 110 units with a total economic value of about 26 billion dollars. In addition, 40 780 trucks and flatbed trailers would be required to transport bales from corn fields and storage sites to biorefineries with a total economic value of 4.0 billion dollars. About 88 899 corn growers need to be contracted with an annual net income of over 2.1 billion dollars. About 1903 storage sites would be required to hold 53.1 million dry tons of inventory after the harvest season. These storage sites would take up about 35 320.2 acres and 4077 loaders with an economic value of 0.4 billion dollars would handle this inventory. The total required workforce to run the logistics operations is estimated to be 50 567. Furthermore, the magnitude of the estimated logistical resources demonstrates the economic and social significance of the corn stover bioeconomy in rural areas in the USA.« less

Estimating the required logistical resources to support the development of a sustainable corn stover bioeconomy in the USA

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

Ebadian, Mahmood; Sokhansanj, Shahabaddine; Webb, Erin

In this paper, the logistical resources required to develop a bioeconomy based on corn stover in the USA are quantified, including field equipment, storage sites, transportation and handling equipment, workforce, corn growers, and corn lands. These resources are essential to mobilize large quantities of corn stover from corn fields to biorefineries. The logistical resources are estimated over the lifetime of the biorefineries. Seventeen corn-growing states are considered for the logistical resource assessment. Over 6.8 billion gallons of cellulosic ethanol can be produced annually from 108 million dry tons of corn stover in these states. The maximum number of required fieldmore » equipment (i.e., choppers, balers, collectors, loaders, and tractors) is estimated to be 194 110 units with a total economic value of about 26 billion dollars. In addition, 40 780 trucks and flatbed trailers would be required to transport bales from corn fields and storage sites to biorefineries with a total economic value of 4.0 billion dollars. About 88 899 corn growers need to be contracted with an annual net income of over 2.1 billion dollars. About 1903 storage sites would be required to hold 53.1 million dry tons of inventory after the harvest season. These storage sites would take up about 35 320.2 acres and 4077 loaders with an economic value of 0.4 billion dollars would handle this inventory. The total required workforce to run the logistics operations is estimated to be 50 567. Furthermore, the magnitude of the estimated logistical resources demonstrates the economic and social significance of the corn stover bioeconomy in rural areas in the USA.« less

Rapid optimization of enzyme mixtures for deconstruction of diverse pretreatment/biomass feedstock combinations.

PubMed

Banerjee, Goutami; Car, Suzana; Scott-Craig, John S; Borrusch, Melissa S; Walton, Jonathan D

2010-10-12

Enzymes for plant cell wall deconstruction are a major cost in the production of ethanol from lignocellulosic biomass. The goal of this research was to develop optimized synthetic mixtures of enzymes for multiple pretreatment/substrate combinations using our high-throughput biomass digestion platform, GENPLAT, which combines robotic liquid handling, statistical experimental design and automated Glc and Xyl assays. Proportions of six core fungal enzymes (CBH1, CBH2, EG1, β-glucosidase, a GH10 endo-β1,4-xylanase, and β-xylosidase) were optimized at a fixed enzyme loading of 15 mg/g glucan for release of Glc and Xyl from all combinations of five biomass feedstocks (corn stover, switchgrass, Miscanthus, dried distillers' grains plus solubles [DDGS] and poplar) subjected to three alkaline pretreatments (AFEX, dilute base [0.25% NaOH] and alkaline peroxide [AP]). A 16-component mixture comprising the core set plus 10 accessory enzymes was optimized for three pretreatment/substrate combinations. Results were compared to the performance of two commercial enzymes (Accellerase 1000 and Spezyme CP) at the same protein loadings. When analyzed with GENPLAT, corn stover gave the highest yields of Glc with commercial enzymes and with the core set with all pretreatments, whereas corn stover, switchgrass and Miscanthus gave comparable Xyl yields. With commercial enzymes and with the core set, yields of Glc and Xyl were highest for grass stovers pretreated by AP compared to AFEX or dilute base. Corn stover, switchgrass and DDGS pretreated with AFEX and digested with the core set required a higher proportion of endo-β1,4-xylanase (EX3) and a lower proportion of endo-β1,4-glucanase (EG1) compared to the same materials pretreated with dilute base or AP. An optimized enzyme mixture containing 16 components (by addition of α-glucuronidase, a GH11 endoxylanase [EX2], Cel5A, Cel61A, Cip1, Cip2, β-mannanase, amyloglucosidase, α-arabinosidase, and Cel12A to the core set) was determined for AFEX-pretreated corn stover, DDGS, and AP-pretreated corn stover. The optimized mixture for AP-corn stover contained more exo-β1,4-glucanase (i.e., the sum of CBH1 + CBH2) and less endo-β1,4-glucanase (EG1 + Cel5A) than the optimal mixture for AFEX-corn stover. Amyloglucosidase and β-mannanase were the two most important enzymes for release of Glc from DDGS but were not required (i.e., 0% optimum) for corn stover subjected to AP or AFEX. As a function of enzyme loading over the range 0 to 30 mg/g glucan, Glc release from AP-corn stover reached a plateau of 60-70% Glc yield at a lower enzyme loading (5-10 mg/g glucan) than AFEX-corn stover. Accellerase 1000 was superior to Spezyme CP, the core set or the 16-component mixture for Glc yield at 12 h, but the 16-component set was as effective as the commercial enzyme mixtures at 48 h. The results in this paper demonstrate that GENPLAT can be used to rapidly produce enzyme cocktails for specific pretreatment/biomass combinations. Pretreatment conditions and feedstock source both influence the Glc and Xyl yields as well as optimal enzyme proportions. It is predicted that it will be possible to improve synthetic enzyme mixtures further by the addition of additional accessory enzymes.

40 CFR 180.182 - Endosulfan; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Apple, wet pomace 5.0 12/31/14 Blueberry 0.3 12/31/14 Corn, sweet, forage 12.0 12/31/14 Corn, sweet, kernel plus cob with husks removed 0.2 12/31/14 Corn, sweet, stover 14.0 12/31/14 Pepper 2.0 12/31/14....0 7/31/15 Corn, sweet, kernel plus cob with husks removed 0.2 7/31/15 Corn, sweet, stover 14.0 7/31...

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

USDA-ARS?s Scientific Manuscript database

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...

40 CFR 180.442 - Bifenthrin; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., leaves 6.0 Coriander, seed 5.0 Corn, field, forage 3.0 Corn, field, grain 0.05 Corn, field, stover 5.0... husk removed 0.05 Corn, sweet, stover 5.0 Cotton, undelinted seed 0.5 Eggplant 0.05 Egg 0.05 Fruit..., seed 0.05 Sheep, fat 1.0 Sheep, meat byproducts 0.1 Sheep, meat 0.5 Soybean, hulls 0.50 Soybean...

40 CFR 180.442 - Bifenthrin; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., leaves 6.0 Coriander, seed 5.0 Corn, field, forage 3.0 Corn, field, grain 0.05 Corn, field, stover 5.0... husk removed 0.05 Corn, sweet, stover 5.0 Cotton, undelinted seed 0.5 Eggplant 0.05 Egg 0.05 Fruit..., seed 0.05 Sheep, fat 1.0 Sheep, meat byproducts 0.1 Sheep, meat 0.5 Soybean, hulls 0.50 Soybean...

Comparison of solid-state to liquid anaerobic digestion of lignocellulosic feedstocks for biogas production.

PubMed

Brown, Dan; Shi, Jian; Li, Yebo

2012-11-01

Lignocellulosic biomass feedstocks (switchgrass, corn stover, wheat straw, yard waste, leaves, waste paper, maple, and pine) were evaluated for methane production under liquid anaerobic digestion (L-AD) and solid-state anaerobic digestion (SS-AD). No significant difference in methane yield between L-AD and SS-AD, except for waste paper and pine, were found. However, the volumetric productivity was 2- to 7-fold greater in the SS-AD system compared with the L-AD system, except for paper. Methane yields from corn stover, wheat straw, and switchgrass were 2-5 times higher than those from yard waste, maple, and pine biomass. Waste paper had a methane yield of only 15 L/kg VS caused by souring during SS-AD due to organic overloading. Pine also had very low biogas yield of 17 L/kg VS, indicating the need for pretreatment prior to SS-AD. The findings of this study can guide future studies to improve the efficiency and stability of SS-AD of lignocellulosic biomass. Copyright © 2012 Elsevier Ltd. All rights reserved.

Comparison of varying operating parameters on heavy metals ecological risk during anaerobic co-digestion of chicken manure and corn stover.

PubMed

Yan, Yilong; Zhang, Liqiu; Feng, Li; Sun, Dezhi; Dang, Yan

2018-01-01

In this study, the potential ecological risk of heavy metals (Mn, Zn, Cu, Ni, As, Cd, Pb, Cr) accumulation from anaerobic co-digestion of chicken manure (CM) and corn stover (CS) was evaluated by comparing different initial substrate concentrations, digestion temperatures, and mixture ratios. Results showed that the highest volumetric methane yield of 20.3±1.4L/L reactor was achieved with a CS:CM ratio of 3:1 (on volatile solid basis) in mesophilic solid state anaerobic digestion (SS-AD). Although co-digestion increased the concentrations of all tested heavy metals and the direct toxicity of some heavy metals, the potential ecological risk index indicated that the digestates were all classified as low ecological risk. The biogasification and risk variation of heavy metals were affected by the operating parameters. These results are significant and should be taken into consideration when optimizing co-digestion of animal manure and crop residues during full-scale projects. Copyright © 2017 Elsevier Ltd. All rights reserved.

Conversion of cellulose rich municipal solid waste blends using ionic liquids: feedstock convertibility and process scale-up

DOE PAGES

Liang, Ling; Li, Chenlin; Xu, Feng; ...

2017-07-24

For this study, sixteen cellulose rich municipal solid waste (MSW) blends were developed and screened using an acid-assisted ionic liquid (IL) deconstruction process. Corn stover and switchgrass were chosen to represent herbaceous feedstocks; non-recyclable paper (NRP) and grass clippings (GC) collected from households were chosen as MSW candidates given their abundance in municipal waste streams. The most promising MSW blend: corn stover/non-recyclable paper (CS/NRP) at 80/20 ratio was identified in milliliter-scale screening based on the sugar yield, feedstock cost, and availability. A successful scale-up (600-fold) of the IL-acidolysis process on the identified CS/NRP blend has been achieved. The sugar andmore » lignin streams were recovered and characterized. Mass and material energy flows of the optimized process were presented. Feedstock cost for MSW blends was also discussed. Results suggest the promising potential of using MSW as a feedstock blending agent for biorefineries while maintaining sufficient performance and low feedstock cost. The bench scale (6 L) study is an essential step in demonstrating the scalability of this IL technology.« less

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.

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.

Conversion of cellulose rich municipal solid waste blends using ionic liquids: feedstock convertibility and process scale-up

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

Liang, Ling; Li, Chenlin; Xu, Feng

For this study, sixteen cellulose rich municipal solid waste (MSW) blends were developed and screened using an acid-assisted ionic liquid (IL) deconstruction process. Corn stover and switchgrass were chosen to represent herbaceous feedstocks; non-recyclable paper (NRP) and grass clippings (GC) collected from households were chosen as MSW candidates given their abundance in municipal waste streams. The most promising MSW blend: corn stover/non-recyclable paper (CS/NRP) at 80/20 ratio was identified in milliliter-scale screening based on the sugar yield, feedstock cost, and availability. A successful scale-up (600-fold) of the IL-acidolysis process on the identified CS/NRP blend has been achieved. The sugar andmore » lignin streams were recovered and characterized. Mass and material energy flows of the optimized process were presented. Feedstock cost for MSW blends was also discussed. Results suggest the promising potential of using MSW as a feedstock blending agent for biorefineries while maintaining sufficient performance and low feedstock cost. The bench scale (6 L) study is an essential step in demonstrating the scalability of this IL technology.« less

Co-solvent pretreatment reduces costly enzyme requirements for high sugar and ethanol yields from lignocellulosic biomass.

PubMed

Nguyen, Thanh Yen; Cai, Charles M; Kumar, Rajeev; Wyman, Charles E

2015-05-22

We introduce a new pretreatment called co-solvent-enhanced lignocellulosic fractionation (CELF) to reduce enzyme costs dramatically for high sugar yields from hemicellulose and cellulose, which is essential for the low-cost conversion of biomass to fuels. CELF employs THF miscible with aqueous dilute acid to obtain up to 95 % theoretical yield of glucose, xylose, and arabinose from corn stover even if coupled with enzymatic hydrolysis at only 2 mgenzyme  gglucan (-1) . The unusually high saccharification with such low enzyme loadings can be attributed to a very high lignin removal, which is supported by compositional analysis, fractal kinetic modeling, and SEM imaging. Subsequently, nearly pure lignin product can be precipitated by the evaporation of volatile THF for recovery and recycling. Simultaneous saccharification and fermentation of CELF-pretreated solids with low enzyme loadings and Saccharomyces cerevisiae produced twice as much ethanol as that from dilute-acid-pretreated solids if both were optimized for corn stover. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of Low Moisture Anhydrous Ammonia (LMAA) Pretreatment at Controlled Ammoniation Temperatures on Enzymatic Hydrolysis of Corn Stover.

PubMed

Cayetano, Roent Dune A; Kim, Tae Hyun

2017-04-01

Corn stover was treated using low-moisture anhydrous ammonia (LMAA) at controlled ammoniation temperature. Moisturized corn stover (50 % moisture) was contacted with anhydrous ammonia (0.1 g NH 3 /g-biomass) in a batch reactor at various temperatures (ambient to 150 °C). After ammoniation at elevated and controlled temperature, ammoniated corn stover was pretreated at various temperatures (60-150 °C) for 72-144 h. Change in composition was marginal at low pretreatment temperature but was relatively severe with pretreatment at high temperature (130-150 °C). The latter resulted in low enzymatic digestibility. It was also observed that extreme levels (either high or low) of residual ammonia affected enzymatic digestibility, while residual ammonia improved by 1.0-1.5 %. The LMAA method enhanced enzymatic digestibility compared to untreated corn stover (29.8 %). The highest glucan and xylan digestibility (84.1 and 73.6 %, respectively) was obtained under the optimal LMAA conditions (i.e., ammoniation at 70 °C for 20 min, followed by pretreatment at 90 °C for 48 h).

Xylitol production from DEO hydrolysate of corn stover by Pichia stipitis YS-30

Treesearch

Rita C.L.B. Rodrigues; William R. Kenealy; Thomas W. Jeffries

2011-01-01

Corn stover that had been treated with vapor-phase diethyl oxalate released a mixture of mono-and oligosaccharides consisting mainly of xylose and glucose. Following overliming and neutralization, a D-xylulokinase mutant of Pichia stipitis, FPL-YS30 (xyl3 -Ä1), converted the stover hydrolysate into xylitol. This research examined the effects of phosphoric or gluconic...

Vertical distribution of structural components in corn stover

DOE PAGES

Johnson, Jane M. F.; Karlen, Douglas L.; Gresham, Garold L.; ...

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 themore » 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.« less

Vertical distribution of structural components in corn stover

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

Johnson, Jane M. F.; Karlen, Douglas L.; Gresham, Garold L.

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 themore » 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.« less

Vertical distribution of structural components in corn stover

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

Jane M. F. Johnson; Douglas L. Karlen; Garold L. Gresham

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

Microwave-assisted co-pyrolysis of brown coal and corn stover for oil production.

PubMed

Zhang, Yaning; Fan, Liangliang; Liu, Shiyu; Zhou, Nan; Ding, Kuan; Peng, Peng; Anderson, Erik; Addy, Min; Cheng, Yanling; Liu, Yuhuan; Li, Bingxi; Snyder, John; Chen, Paul; Ruan, Roger

2018-07-01

The controversial synergistic effect between brown coal and biomass during co-pyrolysis deserves further investigation. This study detailed the oil production from microwave-assisted co-pyrolysis of brown coal (BC) and corn stover (CS) at different CS/BC ratios (0, 0.33, 0.50, 0.67, and 1) and pyrolysis temperatures (500, 550, and 600 °C). The results showed that a higher CS/BC ratio resulted in higher oil yield, and a higher pyrolysis temperature increased oil yield for brown coal and coal/corn mixtures. Corn stover and brown coal showed different pyrolysis characteristics, and positive synergistic effect on oil yield was observed only at CS/BC ratio of 0.33 and pyrolysis temperature of 600 °C. Oils from brown coal mainly included hydrocarbons and phenols whereas oils from corn stover and coal/corn mixtures were dominated by ketones, phenols, and aldehydes. Positive synergistic effects were observed for ketones, aldehydes, acids, and esters whereas negative synergistic effects for hydrocarbons, phenols and alcohols. Copyright © 2018 Elsevier Ltd. All rights reserved.

40 CFR 180.324 - Bromoxynil; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances..., stover 0.2 Corn, pop, grain 0.05 Corn, pop, stover 0.2 Flax, seed 0.1 Garlic 0.1 Grain, aspirated...

Techno-economic analysis for upgrading the biomass-derived ethanol-to-jet blendstocks

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

Tao, Ling; Markham, Jennifer N.; Haq, Zia

Here, this study summarizes the detailed techno-economic analysis of the ethanol-to-jet (ETJ) process based on two different feedstocks (corn grain and corn stover) at the plant scale of 2000 dry metric tons per day. Ethanol biologically derived from biomass is upgraded catalytically to jet blendstocks via alcohol dehydration, olefin oligomerization, and hydrotreating. In both pathways, corn-grain-derived ethanol to jet (corn mill ETJ) and corn-stover-derived ethanol to jet (corn stover ETJ), there are portions of gasoline and diesel produced as coproducts. Two cost bases are used in this study: the minimum jet fuel selling prices (MJSP) for jet-range blendstocks and themore » minimum fuel selling prices (MFSP) for all the hydrocarbons (gasoline, jet, and diesel) produced using a gallon gasoline equivalent (GGE) basis. The n th-plant MJSPs for the two pathways are estimated to be 4.20 per gal for corn mill and 6.14 per gal for corn stover, while MFSPs are 3.91 per GGE for corn mill and 5.37 per GGE for corn stover. If all of the hydrocarbon products (gasoline, jet, and diesel ranges) can be considered as fuel blendstocks using a GGE basis, the total hydrocarbon yield for fuel blendstock is 49.6 GGE per dry ton biomass for corn stover and 71.0 GGE per dry ton biomass for corn grain. The outcome of this study shows that the renewable jet fuel could be cost competitive with fossil derived jet fuel if further improvements could be made to increase process yields (particularly yields of sugars, sugar to ethanol, and ethanol to hydrocarbons), research and development of sustainable feedstocks, and more effective catalytic reaction kinetics. Pioneer plant analysis, which considers the increased capital investment and the decreased plant performance over the nth-plant analysis, is also performed, showing a potential 31%–178% increase in cost compared to the n th-plant assumptions for the dry mill pathway, but with a much wider range of 69%–471% cost increase over the n th-plant assumptions for the corn stover pathway. While there are large differences between the estimated first of a kind plant cost and the targeted nth-plant case, reduction of costs is possible through improvement of the overall process efficiency, yields, reduction in overall capital, co-product revenues and strategically improve performance by process learnings.« less

Techno-economic analysis for upgrading the biomass-derived ethanol-to-jet blendstocks

DOE PAGES

Tao, Ling; Markham, Jennifer N.; Haq, Zia; ...

2016-12-30

Here, this study summarizes the detailed techno-economic analysis of the ethanol-to-jet (ETJ) process based on two different feedstocks (corn grain and corn stover) at the plant scale of 2000 dry metric tons per day. Ethanol biologically derived from biomass is upgraded catalytically to jet blendstocks via alcohol dehydration, olefin oligomerization, and hydrotreating. In both pathways, corn-grain-derived ethanol to jet (corn mill ETJ) and corn-stover-derived ethanol to jet (corn stover ETJ), there are portions of gasoline and diesel produced as coproducts. Two cost bases are used in this study: the minimum jet fuel selling prices (MJSP) for jet-range blendstocks and themore » minimum fuel selling prices (MFSP) for all the hydrocarbons (gasoline, jet, and diesel) produced using a gallon gasoline equivalent (GGE) basis. The n th-plant MJSPs for the two pathways are estimated to be 4.20 per gal for corn mill and 6.14 per gal for corn stover, while MFSPs are 3.91 per GGE for corn mill and 5.37 per GGE for corn stover. If all of the hydrocarbon products (gasoline, jet, and diesel ranges) can be considered as fuel blendstocks using a GGE basis, the total hydrocarbon yield for fuel blendstock is 49.6 GGE per dry ton biomass for corn stover and 71.0 GGE per dry ton biomass for corn grain. The outcome of this study shows that the renewable jet fuel could be cost competitive with fossil derived jet fuel if further improvements could be made to increase process yields (particularly yields of sugars, sugar to ethanol, and ethanol to hydrocarbons), research and development of sustainable feedstocks, and more effective catalytic reaction kinetics. Pioneer plant analysis, which considers the increased capital investment and the decreased plant performance over the nth-plant analysis, is also performed, showing a potential 31%–178% increase in cost compared to the n th-plant assumptions for the dry mill pathway, but with a much wider range of 69%–471% cost increase over the n th-plant assumptions for the corn stover pathway. While there are large differences between the estimated first of a kind plant cost and the targeted nth-plant case, reduction of costs is possible through improvement of the overall process efficiency, yields, reduction in overall capital, co-product revenues and strategically improve performance by process learnings.« less

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

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

Chevanan, Nehru; Womac, A.R.; Bitra, V.S.P.

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 duemore » 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.« less

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

PubMed

Chevanan, Nehru; Womac, Alvin R; Bitra, Venkata S P; Igathinathane, C; Yang, Yuechuan T; Miu, Petre I; Sokhansanj, Shahab

2010-01-01

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/m(3) for switchgrass, 36.1+/-8.6 kg/m(3) for wheat straw, and 52.1+/-10.8 kg/m(3) for corn stover. Mean tapped bulk densities were 81.8+/-26.2 kg/m(3) for switchgrass, 42.8+/-11.7 kg/m(3) for wheat straw, and 58.9+/-13.4 kg/m(3) 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.

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

PubMed

Yoo, Chang Geun; Nghiem, Nhuan P; Hicks, Kevin B; Kim, Tae Hyun

2011-11-01

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% moisture was contacted with anhydrous ammonia in a reactor under nearly ambient conditions. After the ammoniation step, biomass was subjected to a simple pretreatment step at moderate temperatures (40-120°C) for 48-144 h. Pretreated biomass was saccharified and fermented without an additional washing step. With 3% glucan loading of LMAA-treated corn stover under best treatment conditions (0.1g-ammonia+1.0 g-water per g biomass, 80°C, and 84 h), simultaneous saccharification and cofermentation test resulted in 24.9 g/l (89% of theoretical ethanol yield based on glucan+xylan in corn stover). Copyright © 2011 Elsevier Ltd. All rights reserved.

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

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

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

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

Production of Furfural from Process-Relevant Biomass-Derived Pentoses in a Biphasic Reaction System

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

Mittal, Ashutosh; Black, Stuart K.; Vinzant, Todd B.

Furfural is an important fuel precursor which can be converted to hydrocarbon fuels and fuel intermediates. In this work, the production of furfural by dehydration of process-relevant pentose rich corn stover hydrolyzate using a biphasic batch reaction system has been investigated. Methyl isobutyl ketone (MIBK) and toluene have been used to extract furfural and enhance overall furfural yield by limiting its degradation to humins. The effects of reaction time, temperature, and acid concentration (H 2SO 4) on pentose conversion and furfural yield were investigated. For the dehydration of 8 wt % pentose-rich corn stover hydrolyzate under optimum reaction conditions, 0.05more » M H 2SO 4, 170 degrees C for 20 min with MIBK as the solvent, complete conversion of xylose (98-100%) and a furfural yield of 80% were obtained. Under these same conditions, except with toluene as the solvent, the furfural yield was 77%. Additionally, dehydration of process-relevant pentose rich corn stover hydrolyzate using solid acid ion-exchange resins under optimum reaction conditions has shown that Purolite CT275 is as effective as H 2SO 4 for obtaining furfural yields approaching 80% using a biphasic batch reaction system. In conclusion, this work has demonstrated that a biphasic reaction system can be used to process biomass-derived pentose rich sugar hydrolyzates to furfural in yields approaching 80%.« less

Pretreatment of corn stover and hybrid poplar by sodium hydroxide and hydrogen peroxide.

PubMed

Gupta, Rajesh; Lee, Y Y

2010-01-01

Sodium hydroxide and its derivatives are used as pulping reagents, wherein the spent NaOH is recovered in salt form and reused. In this study, use of low concentration NaOH (1-5%) in pretreatment of corn stover and hybrid poplar was investigated. It was done with the understanding that NaOH can be recovered. One of the main objectives in this study is to explore the potential of H(2)O(2) with NaOH for pretreatment of high lignin substrate such as hybrid poplar. Pretreatment time has not been optimized in this study but held constant at 24 h. Corn stover, after treatment with NaOH under moderate conditions, attains near quantitative glucan digestibility. On the other hand, hybrid poplar requires treatment at higher temperature and NaOH concentration to attain acceptable level of digestibility. Supplementation of hydrogen peroxide in the pretreatment significantly raises delignification and digestibility of hybrid poplar. It was also helpful in retaining the carbohydrates in the treated solids. Retention of hemicellulose after pretreatment provides a significant economic benefit as it eliminates the need for detoxifying hemicellulose sugars. As the residual xylan remaining after pretreatment is an impediment to enzymatic digestion of glucan, supplementation of xylanase has significantly increased the digestibility of glucan as well as xylan of the treated hybrid poplar. (c) 2010 American Institute of Chemical Engineers

Production of Furfural from Process-Relevant Biomass-Derived Pentoses in a Biphasic Reaction System

DOE PAGES

Mittal, Ashutosh; Black, Stuart K.; Vinzant, Todd B.; ...

2017-05-16

Furfural is an important fuel precursor which can be converted to hydrocarbon fuels and fuel intermediates. In this work, the production of furfural by dehydration of process-relevant pentose rich corn stover hydrolyzate using a biphasic batch reaction system has been investigated. Methyl isobutyl ketone (MIBK) and toluene have been used to extract furfural and enhance overall furfural yield by limiting its degradation to humins. The effects of reaction time, temperature, and acid concentration (H 2SO 4) on pentose conversion and furfural yield were investigated. For the dehydration of 8 wt % pentose-rich corn stover hydrolyzate under optimum reaction conditions, 0.05more » M H 2SO 4, 170 degrees C for 20 min with MIBK as the solvent, complete conversion of xylose (98-100%) and a furfural yield of 80% were obtained. Under these same conditions, except with toluene as the solvent, the furfural yield was 77%. Additionally, dehydration of process-relevant pentose rich corn stover hydrolyzate using solid acid ion-exchange resins under optimum reaction conditions has shown that Purolite CT275 is as effective as H 2SO 4 for obtaining furfural yields approaching 80% using a biphasic batch reaction system. In conclusion, this work has demonstrated that a biphasic reaction system can be used to process biomass-derived pentose rich sugar hydrolyzates to furfural in yields approaching 80%.« less

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.

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

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

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.

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

PubMed

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

2016-01-01

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

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. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of stover fraction and storage method on glucose production during enzymatic hydrolysis.

PubMed

Montross, M D; Crofcheck, C L

2004-05-01

One avenue for overcoming the economic challenges associated with the production of ethanol from renewable resources is to reduce the cost of the biomass feedstock. The balance between storage costs and benefits depend on the storage method and composition changes of individual stover fractions. Corn stover from bales stored inside and outside of a barn was separated into an interior and exterior layer after approximately 10 months of storage. The cobs, stalks, and leaves and husks were separated, dried, and ground through a 2 mm screen. Stover, sodium acetate (buffer), cellulase, and deionized water were added to 125 ml flasks. The mixture was held at 50 degrees C in an incubator and samples taken for glucose determination. The average glucose concentration after 60 h of hydrolysis from cobs, leaves and husks, and stalks was 10.5, 9.6, and 3.1 g/l, respectively. Cobs, leaves, and husks produced over 300% more glucose than stalks. Storage outside of the barn decreased the glucose production from individual stover components between 4% and 8%. The effect of stover fraction type on glucose production was significant, while the storage treatment effect was not significant. Fractionation of corn stover may be a method to increase the value of corn stover as a feedstock for glucose production.

Sustainable Corn Stover Harvest Strategies

USDA-ARS?s Scientific Manuscript database

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...

Maleic acid treatment of biologically detoxified corn stover liquor

USDA-ARS?s Scientific Manuscript database

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...

40 CFR 180.182 - Endosulfan; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 0.3 12/31/14 Corn, sweet, forage 12.0 12/31/14 Corn, sweet, kernel plus cob with husks removed 0.2 12/31/14 Corn, sweet, stover 14.0 12/31/14 Pepper 2.0 12/31/14 Potato 0.2 12/31/14 Pumpkin 1.0 12/31... plus cob with husks removed 0.2 7/31/15 Corn, sweet, stover 14.0 7/31/15 Pepper 2.0 7/31/15 Potato 0.2...

40 CFR 180.182 - Endosulfan; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 0.3 12/31/14 Corn, sweet, forage 12.0 12/31/14 Corn, sweet, kernel plus cob with husks removed 0.2 12/31/14 Corn, sweet, stover 14.0 12/31/14 Pepper 2.0 12/31/14 Potato 0.2 12/31/14 Pumpkin 1.0 12/31... plus cob with husks removed 0.2 7/31/15 Corn, sweet, stover 14.0 7/31/15 Pepper 2.0 7/31/15 Potato 0.2...

Treatment of different parts of corn stover for high yield and lower polydispersity lignin extraction with high-boiling alkaline solvent.

PubMed

Yang, Mengyao; Rehman, Muhammad Saif Ur; Yan, Tingxuan; Khan, Asad Ullah; Oleskowicz-Popiel, Piotr; Xu, Xia; Cui, Ping; Xu, Jian

2018-02-01

The influence of different parts of corn stover on lignin extraction was investigated. Five kinds of lignin were isolated by the high boiling point solvent extraction from the whole corn stover and four different parts including leaf, husk, bark and pith. The optimal condition was obtained: 6.25 g/L NaOH, 140 °C, 1 h and 60% (v/v) 1,4-butanediol. The extracted lignins were then characterized. FT-IR analysis revealed that all of the lignins were typically herbaceous. The lignin extracted from husk contained more S unit. Gel permeation chromatography analysis showed that it was necessary to separate corn stover into different parts to obtain low polydispersity lignin. The SEM and FT-IR analysis proved that the lignin dissolution was related to the tightness structure presenting a positive correlation with hydrogen bond index. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

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

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

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

Anaerobic co-digestion of chicken manure and corn stover in batch and continuously stirred tank reactor (CSTR).

PubMed

Li, Yeqing; Zhang, Ruihong; He, Yanfeng; Zhang, Chenyu; Liu, Xiaoying; Chen, Chang; Liu, Guangqing

2014-03-01

Anaerobic co-digestion of chicken manure and corn stover in batch and CSTR were investigated. The batch co-digestion tests were performed at an initial volatile solid (VS) concentration of 3gVS/L, carbon-to-nitrogen (C/N) ratio of 20, and retention time of 30d. The methane yield was determined to be 281±12mL/gVSadded. Continuous reactor was carried out with feeding concentration of 12% total solids and C/N ratio of 20 at organic loading rates (OLRs) of 1-4gVS/L/d. Results showed that at OLR of 4gVS/L/d, stable and preferable methane yield of 223±7mL/gVSadded was found, which was equal to energy yield (EY) of 8.0±0.3MJ/kgVSadded. Post-digestion of digestate gave extra EY of 1.5-2.6MJ/kgVSadded. Pyrolysis of digestate provided additional EY of 6.1MJ/kgVSadded. Pyrolysis can be a promising technique to reduce biogas residues and to produce valuable gas products simultaneously. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fuel ethanol production from alkaline peroxide pretreated corn stover

USDA-ARS?s Scientific Manuscript database

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...

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

USDA-ARS?s Scientific Manuscript database

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...

Structural changes of corn stover lignin during acid pretreatment.

PubMed

Moxley, Geoffrey; Gaspar, Armindo Ribeiro; Higgins, Don; Xu, Hui

2012-09-01

In this study, raw corn stover was subjected to dilute acid pretreatments over a range of severities under conditions similar to those identified by the National Renewable Energy Laboratory (NREL) in their techno-economic analysis of biochemical conversion of corn stover to ethanol. The pretreated corn stover then underwent enzymatic hydrolysis with yields above 70 % at moderate enzyme loading conditions. The enzyme exhausted lignin residues were characterized by ³¹P NMR spectroscopy and functional moieties quantified and correlated to enzymatic hydrolysis yields. Results from this study indicated that both xylan solubilization and lignin degradation are important for improving the enzyme accessibility and digestibility of dilute acid pretreated corn stover. At lower pretreatment temperatures, there is a good correlation between xylan solubilization and cellulose accessibility. At higher pretreatment temperatures, lignin degradation correlated better with cellulose accessibility, represented by the increase in phenolic groups. During acid pretreatment, the ratio of syringyl/guaiacyl functional groups also gradually changed from less than 1 to greater than 1 with the increase in pretreatment temperature. This implies that more syringyl units are released from lignin depolymerization of aryl ether linkages than guaiacyl units. The condensed phenolic units are also correlated with the increase in pretreatment temperature up to 180 °C, beyond which point condensation reactions may overtake the hydrolysis of aryl ether linkages as the dominant reactions of lignin, thus leading to decreased cellulose accessibility.

The changes of dominant lactic acid bacteria and their metabolites during corn stover ensiling.

PubMed

Xu, Zhenshang; Zhang, Susu; Zhang, Rongling; Li, Shixu; Kong, Jian

2018-05-15

Monitoring the succession of bacterial populations during corn stover ensiling are helpful for improving the silage quality. Fermentation characteristics were assessed and bacterial communities were described along with the ensiling process. The ensiled corn stover exhibited chemical traits as low pH value (3.92 ± 0.02) and high levels of lactic acid (66.75 ± 1.97 g kg -1 dry matter) which were associated with well ensiled forages, as well as moderate concentrations of acetic acid (19.69 ± 1.51 g kg -1 dry matter) and small amounts of 1, 2-propanediol (4.4 ± 0.11 g kg -1 dry matter). In the early stages of the ensiling process, a significant increase and then reduction of the abundance of species Lactococcus lactis, Leuconostoc pseudomesenteroides, Pediococcus pentosaceus and Weissella sp. were observed. The species Lactobacillus plantarum (Lb. plantarum) group and Lb. brevis grew vigorously, and the species Lb. farciminis and Lb. parafarraginis gradually increased along with the course of ensiling. High-throughput sequencing was successfully used to describe bacterial communities throughout the process of corn stover ensiling. The knowledge about the ecological succession of the dominant lactic acid bacteria could lead to improved ensiling practices and the selection of corn stover silage inoculants. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Corn stover hydrolysate, a lignocellulosic feedstock for polyhydroxyalkanoate biosynthesis: property manipulation using a co-feed strategy with levulinic acid

USDA-ARS?s Scientific Manuscript database

Lignocellulosic feedstocks are interesting materials for bio-based product synthesis because of their availability and cheap cost. Our laboratory utilized corn stover hydrolysate (CSH) as a base feedstock for bacterially-derived polyhydroxyalkanoate biopolymer synthesis. Burkholderia sacchari DSM 17...

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

USDA-ARS?s Scientific Manuscript database

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 ...

Sustainability of corn stover harvest strategies in Pennsylvania

USDA-ARS?s Scientific Manuscript database

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...

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

USDA-ARS?s Scientific Manuscript database

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...

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...

Is Corn Stover Harvest Predictable Using Farm Operation, Technology, and Management Variables?

USDA-ARS?s Scientific Manuscript database

Crop residue management, provision of animal feed or bedding, and increased income potential are some reasons for harvesting corn (Zea mays L.) stover. Reasons for not doing so are that crop residue is essential for restoring soil organic matter, protecting against wind and water erosion, and cyclin...

Development of a system for characterizing biomass quality of lignocellulosic feedstocks for biochemical conversion

NASA Astrophysics Data System (ADS)

Murphy, Patrick Thomas

The purpose of this research was twofold: (i) to develop a system for screening lignocellulosic biomass feedstocks for biochemical conversion to biofuels and (ii) to evaluate brown midrib corn stover as feedstock for ethanol production. In the first study (Chapter 2), we investigated the potential of corn stover from bm1-4 hybrids for increased ethanol production and reduced pretreatment intensity compared to corn stover from the isogenic normal hybrid. Corn stover from hybrid W64A X A619 and respective isogenic bm hybrids was pretreated by aqueous ammonia steeping using ammonium hydroxide concentrations from 0 to 30%, by weight, and the resulting residues underwent simultaneous saccharification and cofermentation (SSCF) to ethanol. Dry matter (DM) digested by SSCF increased with increasing ammonium hydroxide concentration across all genotypes (P>0.0001) from 277 g kg-1 DM in the control to 439 g kg-1 DM in the 30% ammonium hydroxide pretreatment. The bm corn stover materials averaged 373 g kg-1 DM of DM digested by SSCF compared with 335 g kg-1 DM for the normal corn stover (P<0.0001). Of the bm mutations, bm3 had (i) the greatest effect on cell-wall carbohydrate hydrolysis of corn stover, (ii) the lowest initial cell-wall carbohydrate concentration, (iii) the lowest dry matter remaining after pretreatment, and (iv) the highest amount of monosaccharides released during enzymatic hydrolysis. However, bm corn stover did not reduce the severity of aqueous ammonia steeping pretreatment needed to maximize DM hydrolysis during SSCF compared with normal corn stover. In the remaining studies (Chapters 3 thru 5), a system for analyzing the quality of lignocellulosic biomass feedstocks for biochemical conversion to biofuels (i.e., pretreatment, enzymatic hydrolysis, and fermentation) was developed. To accomplish this, a carbohydrate availability model was developed to characterize feedstock quality. The model partitions carbohydrates within a feedstock material into fractions based on their availability to be converted to fermentable sugars, including non-structural carbohydrates (CN) (monosaccharides, starches, oligosaccharides), biochemically available carbohydrates (CB) (structural carbohydrates susceptible to enzymatic hydrolysis) with an associated 1st-order availability rate constant (k B) and unavailable carbohydrates (CU) (hemicellulose and cellulose in close association with lignin). The model partitions the noncarbohydrate dry matter into extractives, lignin, and ash. Quality parameters were determined using a biomass quality assay that combined established wet-chemistry analyses techniques, including total non-structural carbohydrates (TNC), alcohol insoluble residue (AIR), simultaneous saccharification and fermentation (SSCF), and Klason lignin. The next study evaluated multiple high-throughput (HTP) modifications to the original assay methods, including (i) using filter bags with batch sample processing, (ii) replacement of AIR with neutral detergent fiber (NDF) as a cell-wall isolation procedure, and (iii) elimination of the fermentation organism in the SSCF procedures used to determine biochemically available carbohydrates. The original and the HTP assay methods were compared using corn cobs, hybrid poplar, kenaf, and switchgrass. Biochemically available carbohydrates increased with the HTP methods in the corn cobs, hybrid poplar, and switchgrass, but remained the same in the kenaf. Total available carbohydrates increased and unavailable carbohydrates decreased with the HTP methods in the corn cobs and switchgrass and remained the same in the hybrid poplar and kenaf. There were no differences in total carbohydrates (CT) between the two methods. The final study evaluated the variability of biomass quality parameters in a set of corn stover samples, and developed calibration equations for determining parameter values using near infrared reflectance spectroscopy (NIRS). Fifty-two corn stover samples harvested in Iowa and Wisconsin in 2005 and 2006 were analyzed using the HTP assay for determining feedstock quality for biochemical conversion. Non-structural carbohydrates ranged from 84 to 155 g kg -1 DM, CB ranged from 354 to 557 g kg-1 DM, kB ranged from 0.20 to 0.33 h-1, CA ranged from 463 to 699 g kg-1 DM, and neutral detergent lignin (NDL) ranged from 32 to 74 g kg-1 DM. Significant differences (P<0.0001) among samples were observed for all parameters, except for the availability rate constant of CB. (Abstract shortened by UMI.)

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

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

Mohagheghi, Ali; Linger, Jeffrey G.; Yang, Shihui

Complete conversion of the major sugars of biomass including both the C 5 and C 6 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 aremore » 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’s improved performance. In conclusion, we have adapted/evolved Z. mobilis strain 8b for enhanced tolerance to the toxic compounds present in corn stover hydrolysates. The adapted strain SS3 has higher xylose utilization rate and produce more ethanol than the parent strain. We have identified transcriptional changes which may be responsible for these phenotypes, providing foundations for future research directions in improving Z. mobilis as biocatalysts for the production of ethanol or other fuel precursors.« less

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

DOE PAGES

Mohagheghi, Ali; Linger, Jeffrey G.; Yang, Shihui; ...

2015-03-31

Complete conversion of the major sugars of biomass including both the C 5 and C 6 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 aremore » 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’s improved performance. In conclusion, we have adapted/evolved Z. mobilis strain 8b for enhanced tolerance to the toxic compounds present in corn stover hydrolysates. The adapted strain SS3 has higher xylose utilization rate and produce more ethanol than the parent strain. We have identified transcriptional changes which may be responsible for these phenotypes, providing foundations for future research directions in improving Z. mobilis as biocatalysts for the production of ethanol or other fuel precursors.« less

Techno-economic comparison of centralized versus decentralized biorefineries for two alkaline pretreatment processes.

PubMed

Stoklosa, Ryan J; Del Pilar Orjuela, Andrea; da Costa Sousa, Leonardo; Uppugundla, Nirmal; Williams, Daniel L; Dale, Bruce E; Hodge, David B; Balan, Venkatesh

2017-02-01

In this work, corn stover subjected to ammonia fiber expansion (AFEX™) 1 pretreatment or alkaline pre-extraction followed by hydrogen peroxide post-treatment (AHP pretreatment) were compared for their enzymatic hydrolysis yields over a range of solids loadings, enzymes loadings, and enzyme combinations. Process techno-economic models were compared for cellulosic ethanol production for a biorefinery that handles 2000tons per day of corn stover employing a centralized biorefinery approach with AHP or a de-centralized AFEX pretreatment followed by biomass densification feeding a centralized biorefinery. A techno-economic analysis (TEA) of these scenarios shows that the AFEX process resulted in the highest capital investment but also has the lowest minimum ethanol selling price (MESP) at $2.09/gal, primarily due to good energy integration and an efficient ammonia recovery system. The economics of AHP could be made more competitive if oxidant loadings were reduced and the alkali and sugar losses were also decreased. Copyright © 2016 Elsevier Ltd. All rights reserved.

Constructing xylose-assimilating pathways in Pediococcus acidilactici for high titer d-lactic acid fermentation from corn stover feedstock.

PubMed

Qiu, Zhongyang; Gao, Qiuqiang; Bao, Jie

2017-12-01

Xylose-assimilating pathway was constructed in a d-lactic acid producing Pediococcus acidilactici strain and evolutionary adapted to yield a co-fermentation strain P. acidilactici ZY15 with 97.3g/L of d-lactic acid and xylose conversion of 92.6% obtained in the high solids content simultaneous saccharification and co-fermentation (SSCF) of dry dilute acid pretreated and biodetoxified corn stover feedstock. The heterologous genes encoding xylose isomerase (xylA) and xylulokinase (xylB) were screened and integrated into the P. acidilactici chromosome. The metabolic flux to acetic acid in phosphoketolase pathway was re-directed to pentose phosphate pathway by substituting the endogenous phosphoketolase gene (pkt) with the heterologous transketolase (tkt) and transaldolase (tal) genes. The xylose-assimilating ability of the newly constructed P. acidilactici strain was significantly improved by adaptive evolution. This study provided an important strain and process prototype for high titer d-lactic acid production from lignocellulose feedstock with efficient xylose assimilation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Parametric study for the optimization of ionic liquid pretreatment of corn stover

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

Papa, Gabriella; Feldman, Taya; Sale, Kenneth L.

A parametric study of the efficacy of the ionic liquid (IL) pretreatment (PT) of corn stover (CS) using 1-ethyl-3-methylimidazolium acetate ([C 2C 1Im][OAc] ) and cholinium lysinate ([Ch][Lys] ) was conducted. The impact of 50% and 15% biomass loading for milled and non-milled CS on IL-PT was evaluated, as well the impact of 20 and 5 mg enzyme/g glucan on saccharification efficiency. The glucose and xylose released were generated from 32 conditions – 2 ionic liquids (ILs), 2 temperatures, 2 particle sizes (S), 2 solid loadings, and 2 enzyme loadings. Statistical analysis indicates that sugar yields were correlated with lignin andmore » xylan removal and depends on the factors, where S did not explain variation in sugar yields. Both ILs were effective in pretreating large particle sized CS, without compromising sugar yields. The knowledge from material and energy balances is an essential step in directing optimization of sugar recovery at desirable process conditions.« less

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

DOE PAGES

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

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

USDA-ARS?s Scientific Manuscript database

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...

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

USDA-ARS?s Scientific Manuscript database

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...

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.

Improving the conversion of biomass in catalytic fast pyrolysis via white-rot fungal pretreatment.

PubMed

Yu, Yanqing; Zeng, Yelin; Zuo, Jiane; Ma, Fuying; Yang, Xuewei; Zhang, Xiaoyu; Wang, Yujue

2013-04-01

This study investigated the effect of white-rot fungal pretreatment on corn stover conversion in catalytic fast pyrolysis (CFP). Corn stover pretreated by white-rot fungus Irpex lacteus CD2 was fast pyrolyzed alone (non-CFP) and with ZSM-5 zeolite (CFP) in a semi-batch pyroprobe reactor. The fungal pretreatment considerably increased the volatile product yields (predominantly oxygenated compounds) in non-CFP, indicating that fungal pretreatment enhances the corn stover conversion in fast pyrolysis. In the presence of ZSM-5 zeolite, these oxygenated volatiles were further catalytically converted to aromatic hydrocarbons, whose yield increased from 10.03 wt.% for the untreated corn stover to 11.49 wt.% for the pretreated sample. In contrast, the coke yield decreased from 14.29 to 11.93 wt.% in CFP following the fungal pretreatment. These results indicate that fungal pretreatment can enhance the production of valuable aromatics and decrease the amount of undesired coke, and thus has a beneficial effect on biomass conversion in CFP. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pretreatment of corn stover with diluted acetic acid for enhancement of acidogenic fermentation.

PubMed

Zhao, Xu; Wang, Lijuan; Lu, Xuebin; Zhang, Shuting

2014-04-01

A Box-Behnken design of response surface method was used to optimize acetic acid-catalyzed hydrothermal pretreatment of corn stover, in respect to acid concentration (0.05-0.25%), treatment time (5-15 min) and reaction temperature (180-210°C). Acidogenic fermentations with different initial pH and hydrolyzates were also measured to evaluate the optimal pretreatment conditions for maximizing acid production. The results showed that pretreatment with 0.25% acetic acid at 191°C for 7.74 min was found to be the most optimal condition for pretreatment of corn stover under which the production of acids can reach the highest level. Acidogenic fermentation with the hydrolyzate of pretreatment at the optimal condition at the initial pH=5 was shown to be butyric acid type fermentation, producing 21.84 g acetic acid, 7.246 g propionic acid, 9.170 butyric acid and 1.035 g isovaleric acid from 100g of corn stover in 900 g of water containing 2.25 g acetic acid. Copyright © 2014 Elsevier Ltd. All rights reserved.

Kinetics of enzymatic high-solid hydrolysis of lignocellulosic biomass studied by calorimetry.

PubMed

Olsen, Søren N; Lumby, Erik; McFarland, Kc; Borch, Kim; Westh, Peter

2011-03-01

Enzymatic hydrolysis of high-solid biomass (>10% w/w dry mass) has become increasingly important as a key step in the production of second-generation bioethanol. To this end, development of quantitative real-time assays is desirable both for empirical optimization and for detailed kinetic analysis. In the current work, we have investigated the application of isothermal calorimetry to study the kinetics of enzymatic hydrolysis of two substrates (pretreated corn stover and Avicel) at high-solid contents (up to 29% w/w). It was found that the calorimetric heat flow provided a true measure of the hydrolysis rate with a detection limit of about 500 pmol glucose s(-1). Hence, calorimetry is shown to be a highly sensitive real-time method, applicable for high solids, and independent on the complexity of the substrate. Dose-response experiments with a typical cellulase cocktail enabled a multidimensional analysis of the interrelationships of enzyme load and the rate, time, and extent of the reaction. The results suggest that the hydrolysis rate of pretreated corn stover is limited initially by available attack points on the substrate surface (<10% conversion) but becomes proportional to enzyme dosage (excess of attack points) at later stages (>10% conversion). This kinetic profile is interpreted as an increase in polymer end concentration (substrate for CBH) as the hydrolysis progresses, probably due to EG activity in the enzyme cocktail. Finally, irreversible enzyme inactivation did not appear to be the source of reduced hydrolysis rate over time.

The effect of lignin removal by alkaline peroxide pretreatment on the susceptibility of corn stover to purified cellulolytic and xylanolytic enzymes.

PubMed

Selig, Michael J; Vinzant, Todd B; Himmel, Michael E; Decker, Stephen R

2009-05-01

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.

Benefits from Tween during enzymic hydrolysis of corn stover

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

Kaar, W.E.; Holtzapple, M.T.

1998-08-20

Corn stover is a potential substrate for fermentation processes. Previous work with corn stover demonstrated that lime pretreatment rendered it digestible by cellulase; however, high sugar yields required very high enzyme loadings. Because cellulase is a significant cost in biomass conversion processes, the present study focused on improving the enzyme efficiency using Tween 20 and Tween 80; Tween 20 is slightly more effective than Tween 80. The recommended pretreatment conditions for the biomass remained unchanged regardless of whether Tween was added during the hydrolysis. The recommended Tween loading was 0.15 g Tween/g dry biomass. The critical relationship was the Tweenmore » loading on the biomass, not the Tween concentration in solution. The 72-h enzymic conversion of pretreated corn stover using 5 FPU cellulase/g dry biomass at 50 C with Tween 20 as part of the medium was 0.85 g/g for cellulose, 0.66 g/g for xylan, and 0.75 for total polysaccharide; addition of Tween improved the cellulose, xylan, and total polysaccharide conversions by 42, 40, and 42%, respectively. Kinetic analyses showed that Tween improved the enzymic absorption constants, which increased the effective hydrolysis rate compared to hydrolysis without Tween. Furthermore, Tween prevented thermal deactivation of the enzymes, which allows for the kinetic advantage of higher temperature hydrolysis. Ultimate digestion studies showed higher conversions for samples containing Tween, indicating a substrate effect. It appears that Tween improves corn stover hydrolysis through three effects: enzyme stabilizer, lignocellulose disrupter, and enzyme effector.« less

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.

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

Current and potential sustainable corn stover feedstock for biofuel production in the United States

USGS Publications Warehouse

Tan, Zhengxi; Liu, Shu-Guang; Tieszen, Larry L.; Bliss, Norman

2012-01-01

Increased demand for corn (Zea mays L.) stover as a feedstock for cellulosic ethanol raises concerns about agricultural sustainability. Excessive corn stover harvesting could have long-term impacts on soil quality. We estimated current and future stover production and evaluated the potential harvestable stover amount (HSA) that could be used for biofuel feedstock in the United States by defining the minimum stover requirement (MSR) associated with the current soil organic carbon (SOC) content, tillage practices, and crop rotation systems. Here we show that the magnitude of the current HSA is limited (31 Tg y−1, dry matter) due to the high MSR for maintaining the current SOC content levels of soils that have a high carbon content. An alternative definition of MSR for soils with a moderate level of SOC content could significantly elevate the annual HSA to 68.7 Tg, or even to 132.2 Tg if the amount of currently applied manure is counted to partially offset the MSR. In the future, a greater potential for stover feedstock could come from an increase in stover yield, areal harvest index, and/or the total planted area. These results suggest that further field experiments on MSR should be designed to identify differences in MSR magnitude between maintaining SOC content and preventing soil erosion, and to understand the role of current SOC content level in determining MSR from soils with a wide range of carbon contents and climatic conditions.

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

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

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

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 stubblemore » 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, presumably because soil-test P was again in the low range. A soil quality analysis using the Soil Management Assessment Framework (SMAF) with six indicators showed that soils at the continuous corn and rotated sites were functioning at an average of 93 and 83% of their inherent potential, respectively. With good crop management practices, including routine soil-testing, adequate fertilization, maintenance of soil organic matter, sustained soil structure, and prevention of wind, water or tillage erosion, a portion of the corn stover being produced in central Iowa, USA can be harvested in a sustainable manner.« less

40 CFR 180.342 - Chlorpyrifos; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., oil 20 Corn, field, forage 8.0 Corn, field, grain 0.05 Corn, field, refined oil 0.25 Corn, field, stover 8.0 Corn, sweet, forage 8.0 Corn, sweet, kernel plus cob with husk removed 0.05 Corn, sweet...

40 CFR 180.342 - Chlorpyrifos; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., oil 20 Corn, field, forage 8.0 Corn, field, grain 0.05 Corn, field, refined oil 0.25 Corn, field, stover 8.0 Corn, sweet, forage 8.0 Corn, sweet, kernel plus cob with husk removed 0.05 Corn, sweet...

40 CFR 180.342 - Chlorpyrifos; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., oil 20 Corn, field, forage 8.0 Corn, field, grain 0.05 Corn, field, refined oil 0.25 Corn, field, stover 8.0 Corn, sweet, forage 8.0 Corn, sweet, kernel plus cob with husk removed 0.05 Corn, sweet...

40 CFR 180.342 - Chlorpyrifos; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., oil 20 Corn, field, forage 8.0 Corn, field, grain 0.05 Corn, field, refined oil 0.25 Corn, field, stover 8.0 Corn, sweet, forage 8.0 Corn, sweet, kernel plus cob with husk removed 0.05 Corn, sweet...

40 CFR 180.342 - Chlorpyrifos; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., oil 20 Corn, field, forage 8.0 Corn, field, grain 0.05 Corn, field, refined oil 0.25 Corn, field, stover 8.0 Corn, sweet, forage 8.0 Corn, sweet, kernel plus cob with husk removed 0.05 Corn, sweet...

Detoxification of corn stover and corn starch pyrolysis liquors by ligninolytic enzymes of Phanerochaete chrysosporium.

PubMed

Khiyami, Mohammad A; Pometto, Anthony L; Brown, Robert C

2005-04-20

Phanerochaete chrysosporium (ATCC 24725) shake flask culture with 3 mM veratryl alcohol addition on day 3 was able to grow and detoxify different concentrations of diluted corn stover (Dcs) and diluted corn starch (Dst) pyrolysis liquors [10, 25, and 50% (v/v)] in defined media. GC-MS analysis of reaction products showed a decrease and change in some compounds. In addition, the total phenolic assay with Dcs samples demonstrated a decrease in the phenolic compounds. A bioassay employing Lactobacillus casei growth and lactic acid production was developed to confirm the removal of toxic compounds from 10 and 25% (v/v) Dcs and Dst by the lignolytic enzymes, but not from 50% (v/v) Dcs and Dst. The removal did not occur when sodium azide or cycloheximide was added to Ph. chrysosporium culture media, confirming the participation of lignolytic enzymes in the detoxification process. A concentrated enzyme preparation decreased the phenolic compounds in 10% (v/v) corn stover and corn starch pyrolysis liquors to the same extent as the fungal cultures.

Sustainability of corn stover harvest strategies in Pennsylvania

Treesearch

Paul R. Adler; Benjamin M. Rau; Gregory W. Roth

2015-01-01

Pennsylvania farmers have a long history of harvesting corn (Zea mays L.) 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 of cover crops, no-till, and...

Effect of bedding materials on concentration of odorous compounds and Escherichia coli in beef cattle bedded manure packs

USDA-ARS?s Scientific Manuscript database

The objectives of this study were to determine the effect of bedding material (corn stover, soybean stover, wheat straw, switchgrass, wood chips, wood shavings, corn cobs, and shredded paper) on concentration of odorous volatile organic compounds (VOC) in bedded pack material, and to determine the e...

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

USDA-ARS?s Scientific Manuscript database

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...

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

USDA-ARS?s Scientific Manuscript database

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...

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

USDA-ARS?s Scientific Manuscript database

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...

NREL: Renewable Resource Data Center - Biomass Resource Information

Science.gov Websites

Biomass Resource Information Photo of corn stover biomass resource Corn stover The Renewable Resource Data Center (RReDC) offers a collection of data and tools to assist with biomass resource research . Learn more about RReDC's biomass resource: Data Models and tools Publications Related links Biomass

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

USDA-ARS?s Scientific Manuscript database

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...

40 CFR 180.232 - Butylate; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Corn, field, forage 0.1 Corn, field, grain 0.1 Corn, field, stover 0.1 Corn, pop, forage 0.1 Corn, pop, grain 0.1 Corn, sweet, forage 0.1 Corn, sweet, kernel plus cob with husks removed 0.1 (b) Section 18...

40 CFR 180.232 - Butylate; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Corn, field, forage 0.1 Corn, field, grain 0.1 Corn, field, stover 0.1 Corn, pop, forage 0.1 Corn, pop, grain 0.1 Corn, sweet, forage 0.1 Corn, sweet, kernel plus cob with husks removed 0.1 (b) Section 18...

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 PAGES

Chen, Xiaowen; Kuhn, Erik; Jennings, Edward W.; ...

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

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 Office of Scientific and Technical Information (OSTI.GOV)

Chen, Xiaowen; Kuhn, Erik; Jennings, Edward W.

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

Extent of pyrolysis impacts on fast pyrolysis biochar properties.

PubMed

Brewer, Catherine E; Hu, Yan-Yan; Schmidt-Rohr, Klaus; Loynachan, Thomas E; Laird, David A; Brown, Robert C

2012-01-01

A potential concern about the use of fast pyrolysis rather than slow pyrolysis biochars as soil amendments is that they may contain high levels of bioavailable C due to short particle residence times in the reactors, which could reduce the stability of biochar C and cause nutrient immobilization in soils. To investigate this concern, three corn ( L.) stover fast pyrolysis biochars prepared using different reactor conditions were chemically and physically characterized to determine their extent of pyrolysis. These biochars were also incubated in soil to assess their impact on soil CO emissions, nutrient availability, microorganism population growth, and water retention capacity. Elemental analysis and quantitative solid-state C nuclear magnetic resonance spectroscopy showed variation in O functional groups (associated primarily with carbohydrates) and aromatic C, which could be used to define extent of pyrolysis. A 24-wk incubation performed using a sandy soil amended with 0.5 wt% of corn stover biochar showed a small but significant decrease in soil CO emissions and a decrease in the bacteria:fungi ratios with extent of pyrolysis. Relative to the control soil, biochar-amended soils had small increases in CO emissions and extractable nutrients, but similar microorganism populations, extractable NO levels, and water retention capacities. Corn stover amendments, by contrast, significantly increased soil CO emissions and microbial populations, and reduced extractable NO. These results indicate that C in fast pyrolysis biochar is stable in soil environments and will not appreciably contribute to nutrient immobilization. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Comparative study of corn stover pretreated by dilute acid and cellulose solvent-based lignocellulose fractionation: Enzymatic hydrolysis, supramolecular structure, and substrate accessibility.

PubMed

Zhu, Zhiguang; Sathitsuksanoh, Noppadon; Vinzant, Todd; Schell, Daniel J; McMillan, James D; Zhang, Y-H Percival

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 approximately 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(2)/g, nearly twice that of the DA-pretreated biomass (5.89 m(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. (c) 2009 Wiley Periodicals, Inc.

The Effect of Organic Phosphorus and Nitrogen Enriched Manure on Nutritive Value of Sweet Corn Stover

NASA Astrophysics Data System (ADS)

Lukiwati, D. R.; Pujaningsih, R. I.; Murwani, R.

2018-02-01

The experiment aimed to evaluate the effect of some manure enriched with phosphorus (P) and nitrogen (N) organic (‘manure plus’) on crude protein and mineral production of sweet corn (Zea mays saccharata)and quality of fermented stover as livestock feed. A field experiment was conducted on a vertisol soil (low pH, nitrogen and low available Bray II extractable P). Randomized block design with 9 treatments in 3 replicates was used in this experiment. The treatments were T1(TSP), T2 (SA), T3 (TSP+SA), T4 (manure), T5 (manure+PR), T6 (manure+guano), T7 (manure+N-legume), T8 (manure+PR+N-legume), T9 (manure +guano+N-legume). Data were analyzed using analysis of variance (ANOVA) and the differences between treatment means were examined by Duncan Multiple Range Test (DMRT). Results of the experiment showed that the treatment significantly affected to the crude protein and calcium production of stover and nutrient concentration of fermented stover, but it is not affected to P production of stover. The result of DMRT showed that the effect of ‘manure plus’ was not significantly different on CP and Ca production of stover, mineral concentration, in vitro DMD and OMD of fermented stover, compared to inorganic fertilization. Conclusion, manure enriched with organic NP, resulted in similar on CP and Ca production of stover and nutrient concentration of fermented stover compared to inorganic fertilizer. Thus, organic-NP enriched manure could be an alternative and viable technology to utilize low grade of phosphate rock, guano and Gliricidea sepium to produce sweet corn in vertisol soil.

40 CFR 180.523 - Metaldehyde; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

....15 Cactus 0.07 Caneberry subgroup 13-07A 0.15 Corn, field, forage 0.30 Corn, field, grain 0.05 Corn, field, stover 0.10 Corn, sweet, forage 0.30 Corn, sweet, kernel plus cob with husks removed 0.05 Corn...

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

USDA-ARS?s Scientific Manuscript database

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...

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

USDA-ARS?s Scientific Manuscript database

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...

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

USDA-ARS?s Scientific Manuscript database

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 ...

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

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

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

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

Qin, Zhangcai; Dunn, Jennifer B.; Kwon, Hoyoung

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

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. Copyright © 2012. Published by Elsevier Ltd.

40 CFR 180.535 - Fluroxypyr 1-methylheptyl ester; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Cattle, meat 0.1 Cattle, meat byproducts 0.1 Corn, field, forage 1.0 Corn, field, grain 0.02 Corn, field, stover 0.5 Corn, sweet, forage 1.0 Corn, sweet, kernel plus cob with husks removed 0.02 Corn, sweet...

Environmental Impacts of Stover Removal in the Corn Belt

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

Alicia English; Wallace E. Tyner; Juan Sesmero

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.

A novel film-pore-surface diffusion model to explain the enhanced enzyme adsorption of corn stover pretreated by ultrafine grinding.

PubMed

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

2016-01-01

Ultrafine grinding is an environmentally friendly pretreatment that can alter the degree of polymerization, the porosity and the specific surface area of lignocellulosic biomass and can, thus, enhance cellulose hydrolysis. Enzyme adsorption onto the substrate is a prerequisite for the enzymatic hydrolysis process. Therefore, it is necessary to investigate the enzyme adsorption properties of corn stover pretreated by ultrafine grinding. The ultrafine grinding pretreatment was executed on corn stover. The results showed that ultrafine grinding pretreatment can significantly decrease particle size [from 218.50 μm of sieve-based grinding corn stover (SGCS) to 17.45 μm of ultrafine grinding corn stover (UGCS)] and increase the specific surface area (SSA), pore volume (PV) and surface composition (SSA: from 1.71 m(2)/g of SGCS to 2.63 m(2)/g of UGCS, PV: from 0.009 cm(3)/g of SGCS to 0.024 m(3)/g of UGCS, cellulose surface area: from 168.69 m(2)/g of SGCS to 290.76 m(2)/g of UGCS, lignin surface area: from 91.46 m(2)/g of SGCS to 106.70 m(2)/g of UGCS). The structure and surface composition changes induced by ultrafine grinding increase the enzyme adsorption capacity from 2.83 mg/g substrate of SGCS to 5.61 mg/g substrate of UGCS. A film-pore-surface diffusion model was developed to simultaneously predict the enzyme adsorption kinetics of both the SGCS and UGCS. Satisfactory predictions could be made with the model based on high R (2) and low RMSE values (R (2) = 0.95 and RMSE = 0.16 mg/g for the UGCS, R (2) = 0.93 and RMSE = 0.09 mg/g for the SGCS). The model was further employed to analyze the rate-limiting steps in the enzyme adsorption process. Although both the external-film and internal-pore mass transfer are important for enzyme adsorption on the SGCS and UGCS, the UGCS has a lower internal-pore resistance compared to the SGCS. Ultrafine grinding pretreatment can enhance the enzyme adsorption onto corn stover by altering structure and surface composition. The film-pore-surface diffusion model successfully captures features on enzyme adsorption on ultrafine grinding pretreated corn stover. These findings identify wherein the probable rate-limiting factors for the enzyme adsorption reside and could, therefore, provide a basis for enhanced cellulose hydrolysis processes.

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

2015-06-01

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.

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

USGS Publications Warehouse

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.

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

Final Technical Report

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

Aristos Aristidou Natureworks); Robert Kean; Tom Schechinger

2007-10-01

The two main objectives of this project were: 1) to develop and test technologies to harvest, transport, store, and separate corn stover to supply a clean raw material to the bioproducts industry, and 2) engineer fermentation systems to meet performance targets for lactic acid and ethanol manufacturers. Significant progress was made in testing methods to harvest corn stover in a “single pass” harvest mode (collect corn grain and stover at the same time). This is technically feasible on small scale, but additional equipment refinements will be needed to facilitate cost effective harvest on a larger scale. Transportation models were developed,more » which indicate that at a corn stover yield of 2.8 tons/acre and purchase price of $35/ton stover, it would be unprofitable to transport stover more than about 25 miles; thus suggesting the development of many regional collection centers. Therefore, collection centers should be located within about 30 miles of the farm, to keep transportation costs to an acceptable level. These collection centers could then potentially do some preprocessing (to fractionate or increase bulk density) and/or ship the biomass by rail or barge to the final customers. Wet storage of stover via ensilage was tested, but no clear economic advantages were evident. Wet storage eliminates fire risk, but increases the complexity of component separation and may result in a small loss of carbohydrate content (fermentation potential). A study of possible supplier-producer relationships, concluded that a “quasi-vertical” integration model would be best suited for new bioproducts industries based on stover. In this model, the relationship would involve a multiyear supply contract (processor with purchase guarantees, producer group with supply guarantees). Price will likely be fixed or calculated based on some formula (possibly a cost plus). Initial quality requirements will be specified (but subject to refinement).Producers would invest in harvest/storage/transportation equipment and the processor would build and operate the plant. Pilot fermentation studies demonstrated dramatic improvements in yields and rates with optimization of batch fermentor parameters. Demonstrated yields and rates are approaching those necessary for profitable commercial operation for production of ethanol or lactic acid. The ability of the biocatalyst to adapt to biomass hydrolysate (both biomass sugars and toxins in the hydrolysate) was demonstrated and points towards ultimate successful commercialization of the technology. However, some of this work will need to be repeated and possibly extended to adapt the final selected biocatalyst for the specific commercial hydrolysate composition. The path from corn stover in the farm field to final products, involves a number of steps. Each of these steps has options, problems, and uncertainties; thus creating a very complex multidimensional obstacle to successful commercial development. Through the tasks of this project, the technical and commercial uncertainties of many of these steps have been addressed; thus providing for a clearer understanding of paths forward and commercial viability of a corn stover-based biorefinery.« less

Response surface methodology (RSM) to evaluate moisture effects on corn stover in recovering xylose by DEO hydrolysis

Treesearch

Rita C.L.B. Rodrigues; William R. Kenealy; Diane Dietrich; Thomas W. Jeffries

2012-01-01

Response surface methodology (RSM), based on a 22 full factorial design, evaluated the moisture effects in recovering xylose by diethyloxalate (DEO) hydrolysis. Experiments were carried out in laboratory reactors (10 mL glass ampoules) containing corn stover (0.5 g) properly ground. The ampoules were kept at 160 °C for 90 min. Both DEO...

Odorous volatile organic compounds, Escherichia coli, and nutrient concentrations when kiln-dried pine chips and corn stover bedding are used in beef bedded manure packs

USDA-ARS?s Scientific Manuscript database

Pine (Pinus spp.) bedding has been shown to lower the concentration of odorous volatile organic compounds (VOCs) and pathogenic bacteria compared with corn (Zea mays L.) stover bedding, but availability and cost limit the use of pine bedding in cattle confinement facilities. The objectives of this s...

Effect of xylanase supplementation of cellulase on digestion of corn stover solids prepared by leading pretreatment technologies.

PubMed

Kumar, Rajeev; Wyman, Charles E

2009-09-01

Solids resulting from pretreatment of corn stover by ammonia fiber expansion (AFEX), ammonia recycled percolation (ARP), controlled pH, dilute acid, lime, and sulfur dioxide (SO(2)) technologies were hydrolyzed by enzyme cocktails based on cellulase supplemented with beta-glucosidase at an activity ratio of 1:2, respectively, and augmented with up to 11.0 g xylanase protein/g cellulase protein for combined cellulase and beta-glucosidase mass loadings of 14.5 and 29.0 mg protein (about 7.5 and 15 FPU, respectively)/g of original potential glucose. It was found that glucose release increased nearly linearly with residual xylose removal by enzymes for all pretreatments despite substantial differences in their relative yields. The ratio of the fraction of glucan removed by enzymes to that for xylose was defined as leverage and correlated statistically at two combined cellulase and beta-glucosidase mass loadings with pretreatment type. However, no direct relationship was found between leverage and solid features following different pretreatments such as residual xylan or acetyl content. However, acetyl content not only affected how xylanase impacted cellulase action but also enhanced accessibility of cellulose and/or cellulase effectiveness, as determined by hydrolysis with purified CBHI (Cel7A). Statistical modeling showed that cellulose crystallinity, among the main substrate features, played a vital role in cellulase-xylanase interactions, and a mechanism is suggested to explain the incremental increase in glucose release with xylanase supplementation.

Cover crop root, shoot, and rhizodeposit contributions to soil carbon in a no- till corn bioenergy cropping system

NASA Astrophysics Data System (ADS)

Austin, E.; Grandy, S.; Wickings, K.; McDaniel, M. D.; Robertson, P.

2016-12-01

Crop residues are potential biofuel feedstocks, but residue removal may result in reduced soil carbon (C). The inclusion of a cover crop in a corn bioenergy system could provide additional biomass and as well as help to mitigate the negative effects of residue removal by adding belowground C to stable soil C pools. In a no-till continuous corn bioenergy system in the northern portion of the US corn belt, we used 13CO2 pulse labeling to trace C in a winter rye (secale cereale) cover crop into different soil C pools for two years following rye termination. Corn stover contributed 66 (another 163 was in harvested corn stover), corn roots 57, rye shoot 61, rye roots 59, and rye rhizodeposits 27 g C m-2 to soil C. Five months following cover crop termination, belowground cover crop inputs were three times more likely to remain in soil C pools and much of the root-derived C was in mineral- associated soil fractions. Our results underscore the importance of cover crop roots vs. shoots as a source of soil C. Belowground C inputs from winter cover crops could substantially offset short term stover removal in this system.

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

On-site cellulase production and efficient saccharification of corn stover employing cbh2 overexpressing Trichoderma reesei with novel induction system.

PubMed

Li, Yonghao; Zhang, Xiaoyue; Xiong, Liang; Mehmood, Muhammad Aamer; Zhao, Xinqing; Bai, Fengwu

2017-08-01

Although on-site cellulase production offers cost-effective saccharification of lignocellulosic biomass, low enzyme titer is still a barrier for achieving robustness. In the present study, a strain of T. reesei was developed for enhanced production of cellulase via overexpression of Cellobiohydrolase II. Furthermore, optimum enzyme production was achieved using a novel inducer mixture containing synthesized glucose-sophorose (MGD) and alkali pre-treated corn stover (APCS). Within 60h, a remarkably higher cellulase productivity and activity were achieved in the fed-batch fermentation using the optimized ratio of MGD and APCS in the inducer mixture, compared to those reported using cellulosic biomass as the sole inducer. After the enzyme production, APCS was added directly into the fermentation broth at 20% solid loading, which produced 122.5g/L glucose and 40.21g/L xylose, leading to the highest yield reported so far. The improved enzyme titers during on-site cellulase production would benefit cost-competitive saccharification of lignocellulosic biomass. Copyright © 2017 Elsevier Ltd. All rights reserved.

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. Copyright © 2015 Elsevier B.V. All rights reserved.

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

DOE PAGES

Brunecky, Roman; Hobdey, Sarah E.; Taylor, Larry E.; ...

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

Fermentation of wet-exploded corn stover for the production of volatile fatty acids.

PubMed

Murali, Nanditha; Fernandez, Sebastian; Ahring, Birgitte Kiaer

2017-03-01

Volatile fatty acids (VFA) have been used as platform molecules for production of biofuels and bioproducts. In the current study, we examine the VFA production from wet-exploded corn stover through anaerobic fermentation using rumen bacteria. The total VFA yield (acetic acid equivalents) was found to increase from 22.8g/L at 2.5% total solids (TS) to 40.8g/L at 5% TS. It was found that the acetic acid concentration increased from 10g/L to 22g/L at 2.5% and 5% TS, respectively. An increased propionic acid production was seen between day 10 and 20 at 5% TS. Valeric acid (4g/L) was produced at 5% TS and not at 2.5% TS. Composition analysis showed that 50% of the carbohydrates were converted to VFA at 5% TS and 33% at 2.5% TS. Our results show that rumen fermentation of lignocellulosic biomass after wet explosion can produce high concentrations of VFA without addition of external enzymes of importance for the process economics of lignocellulosic biorefineries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impact of ammonia fiber expansion (AFEX) pretreatment on energy consumption during drying, grinding, and pelletization of corn stover

DOE PAGES

Bonner, Ian Jeffery; Thompson, David N.; Plummer, Mitchell; ...

2016-01-08

Pretreatment and densification of biomass can increase the viability of bioenergy production by providing a feedstock that is readily hydrolyzed and able to be transported greater distances. Ammonia Fiber Expansion (AFEX) is one such method targeted for use at distributed depots to create a value-added and densified feedstock for bioenergy use. However, the pretreatment process results in a high-moisture material that must be dried, further size reduced, and pelletized; all of which are energy intensive processes. This work quantifies the energy consumption required to dry, grind, and densify AFEX pretreated corn stover compared to non-pretreated stover and explores the potentialmore » of reduced drying as a means to conserve energy. The purpose of this work is to understand whether material property changes resulting from AFEX pretreatment influence the material performance in downstream formatting operations. Material properties, heat balance equations, and a rotary drum dryer model were used to model a commercial scale rotary drum dryer for AFEX pretreated corn stover, showing the potential to reduce dryer energy consumption by up to 36% compared to non-pretreated corn stover. Laboratory measured grinding and pelleting energies were both very sensitive to material moisture content. Overall, the total energy required for drying, grinding, and pelleting amounts to a savings of up to 20 kWh/dry ton for the AFEX pretreated material when dried to a low moisture content, equating to up to 0.55 /kg savings for gas and electricity. Grinding and pelleting of high moisture AFEX pretreated stover was shown to be more costly than the savings collected through reduced drying. Furthermore, while the energy and cost savings shown here are modest, the results help to highlight operational challenges and opportunities for continued improvement.« less

Impact of ammonia fiber expansion (AFEX) pretreatment on energy consumption during drying, grinding, and pelletization of corn stover

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

Bonner, Ian Jeffery; Thompson, David N.; Plummer, Mitchell

Pretreatment and densification of biomass can increase the viability of bioenergy production by providing a feedstock that is readily hydrolyzed and able to be transported greater distances. Ammonia Fiber Expansion (AFEX) is one such method targeted for use at distributed depots to create a value-added and densified feedstock for bioenergy use. However, the pretreatment process results in a high-moisture material that must be dried, further size reduced, and pelletized; all of which are energy intensive processes. This work quantifies the energy consumption required to dry, grind, and densify AFEX pretreated corn stover compared to non-pretreated stover and explores the potentialmore » of reduced drying as a means to conserve energy. The purpose of this work is to understand whether material property changes resulting from AFEX pretreatment influence the material performance in downstream formatting operations. Material properties, heat balance equations, and a rotary drum dryer model were used to model a commercial scale rotary drum dryer for AFEX pretreated corn stover, showing the potential to reduce dryer energy consumption by up to 36% compared to non-pretreated corn stover. Laboratory measured grinding and pelleting energies were both very sensitive to material moisture content. Overall, the total energy required for drying, grinding, and pelleting amounts to a savings of up to 20 kWh/dry ton for the AFEX pretreated material when dried to a low moisture content, equating to up to 0.55 /kg savings for gas and electricity. Grinding and pelleting of high moisture AFEX pretreated stover was shown to be more costly than the savings collected through reduced drying. Furthermore, while the energy and cost savings shown here are modest, the results help to highlight operational challenges and opportunities for continued improvement.« less

The effect of biomass densification on structural sugar release and yield in biofuel feedstock and feedstock blends

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

Wolfrum, Edward J.; Nagle, Nicholas J.; Ness, Ryan M.

In this work, we examined the behavior of feedstock blends and the effect of a specific feedstock densification strategy (pelleting) on the release and yield of structural carbohydrates in a laboratory-scale dilute acid pretreatment (PT) and enzymatic hydrolysis (EH) assay. We report overall carbohydrate release and yield from the two-stage PT-EH assay for five single feedstocks (two corn stovers, miscanthus, switchgrass, and hybrid poplar) and three feedstock blends (corn stover-switchgrass, corn stover-switchgrass-miscanthus, and corn stover-switchgrass-hybrid poplar). We first examined the experimental results over time to establish the robustness of the PT-EH assay, which limits the precision of the experimental results.more » The use of two different control samples in the assay enabled us to identify (and correct for) a small bias in the EH portion of the combined assay for some runs. We then examined the effect of variable pretreatment reaction conditions (residence time, acid loading, and reactor temperature) on the conversion of a single feedstock (single-pass corn stover, CS-SP) in order to establish the range of pretreatment reaction conditions likely to provide optimal conversion data. Finally, we applied the assay to the 16 materials (8 feedstocks in 2 formats, loose and pelleted) over a more limited range of pretreatment experimental conditions. The four herbaceous feedstocks behaved similarly, while the hybrid poplar feedstock required higher pretreatment temperatures for optimal results. As expected, the yield data for three blended feedstocks were the average of the yield data for the individual feedstocks. As a result, the pelleting process appears to provide a slightly positive effect on overall total sugar yield.« less

The effect of biomass densification on structural sugar release and yield in biofuel feedstock and feedstock blends

DOE PAGES

Wolfrum, Edward J.; Nagle, Nicholas J.; Ness, Ryan M.; ...

2017-01-13

In this work, we examined the behavior of feedstock blends and the effect of a specific feedstock densification strategy (pelleting) on the release and yield of structural carbohydrates in a laboratory-scale dilute acid pretreatment (PT) and enzymatic hydrolysis (EH) assay. We report overall carbohydrate release and yield from the two-stage PT-EH assay for five single feedstocks (two corn stovers, miscanthus, switchgrass, and hybrid poplar) and three feedstock blends (corn stover-switchgrass, corn stover-switchgrass-miscanthus, and corn stover-switchgrass-hybrid poplar). We first examined the experimental results over time to establish the robustness of the PT-EH assay, which limits the precision of the experimental results.more » The use of two different control samples in the assay enabled us to identify (and correct for) a small bias in the EH portion of the combined assay for some runs. We then examined the effect of variable pretreatment reaction conditions (residence time, acid loading, and reactor temperature) on the conversion of a single feedstock (single-pass corn stover, CS-SP) in order to establish the range of pretreatment reaction conditions likely to provide optimal conversion data. Finally, we applied the assay to the 16 materials (8 feedstocks in 2 formats, loose and pelleted) over a more limited range of pretreatment experimental conditions. The four herbaceous feedstocks behaved similarly, while the hybrid poplar feedstock required higher pretreatment temperatures for optimal results. As expected, the yield data for three blended feedstocks were the average of the yield data for the individual feedstocks. As a result, the pelleting process appears to provide a slightly positive effect on overall total sugar yield.« less

Mathematical tool from corn stover TGA to determine its composition.

PubMed

Freda, Cesare; Zimbardi, Francesco; Nanna, Francesco; Viola, Egidio

2012-08-01

Corn stover was treated by steam explosion process at four different temperatures. A fraction of the four exploded matters was extracted by water. The eight samples (four from steam explosion and four from water extraction of exploded matters) were analysed by wet chemical way to quantify the amount of cellulose, hemicellulose and lignin. Thermogravimetric analysis in air atmosphere was executed on the eight samples. A mathematical tool was developed, using TGA data, to determine the composition of corn stover in terms of cellulose, hemicellulose and lignin. It uses the biomass degradation temperature as multiple linear function of the cellulose, hemicellulose and lignin content of the biomass with interactive terms. The mathematical tool predicted cellulose, hemicellulose and lignin contents with average absolute errors of 1.69, 5.59 and 0.74 %, respectively, compared to the wet chemical method.

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

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

Elander, Rick

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 representativemore » large volume, sustainable feedstock.« less

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.

Rich biotin content in lignocellulose biomass plays the key role in determining cellulosic glutamic acid accumulation by Corynebacterium glutamicum.

PubMed

Wen, Jingbai; Xiao, Yanqiu; Liu, Ting; Gao, Qiuqiang; Bao, Jie

2018-01-01

Lignocellulose is one of the most promising alternative feedstocks for glutamic acid production as commodity building block chemical, but the efforts by the dominant industrial fermentation strain Corynebacterium glutamicum failed for accumulating glutamic acid using lignocellulose feedstock. We identified the existence of surprisingly high biotin concentration in corn stover hydrolysate as the determining factor for the failure of glutamic acid accumulation by Corynebacterium glutamicum . Under excessive biotin content, induction by penicillin resulted in 41.7 ± 0.1 g/L of glutamic acid with the yield of 0.50 g glutamic acid/g glucose. Our further investigation revealed that corn stover contained 353 ± 16 μg of biotin per kg dry solids, approximately one order of magnitude greater than the biotin in corn grain. Most of the biotin remained stable during the biorefining chain and the rich biotin content in corn stover hydrolysate almost completely blocked the glutamic acid accumulation. This rich biotin existence was found to be a common phenomenon in the wide range of lignocellulose biomass and this may be the key reason why the previous studies failed in cellulosic glutamic acid fermentation from lignocellulose biomass. The extended recording of the complete members of all eight vitamin B compounds in lignocellulose biomass further reveals that the major vitamin B members were also under the high concentration levels even after harsh pretreatment. The high content of biotin in wide range of lignocellulose biomass feedstocks and the corresponding hydrolysates was discovered and it was found to be the key factor in determining the cellulosic glutamic acid accumulation. The highly reserved biotin and the high content of their other vitamin B compounds in biorefining process might act as the potential nutrients to biorefining fermentations. This study creates a new insight that lignocellulose biorefining not only generates inhibitors, but also keeps nutrients for cellulosic fermentations.

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

USDA-ARS?s Scientific Manuscript database

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...

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

PubMed

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

2011-03-01

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

Effect of acid, steam explosion, and size reduction pretreatments on bio-oil production from sweetgum, switchgrass, and corn stover.

PubMed

Wang, Hui; Srinivasan, Radhakrishnan; Yu, Fei; Steele, Philip; Li, Qi; Mitchell, Brian; Samala, Aditya

2012-05-01

Bio-oil produced from biomass by fast pyrolysis has the potential to be a valuable substitute for fossil fuels. In a recent work on pinewood, we found that pretreatment alters the structure and chemical composition of biomass, which influence fast pyrolysis. In this study, we evaluated dilute acid, steam explosion, and size reduction pretreatments on sweetgum, switchgrass, and corn stover feedstocks. Bio-oils were produced from untreated and pretreated feedstocks in an auger reactor at 450 °C. The bio-oil's physical properties of pH, water content, acid value, density, and viscosity were measured. The chemical characteristics of the bio-oils were determined by gas chromatography-mass spectrometry. The results showed that bio-oil yield and composition were influenced by the pretreatment method and feedstock type. Bio-oil yields of 52, 33, and 35 wt% were obtained from medium-sized (0.68-1.532 mm) untreated sweetgum, switchgrass, and corn stover, respectively, which were higher than the yields from other sizes. Bio-oil yields of 56, 46, and 51 wt% were obtained from 1% H(2)SO(4)-treated medium-sized sweetgum, switchgrass, and corn stover, respectively, which were higher than the yields from untreated and steam explosion treatments.

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.

Updates to the Corn Ethanol Pathway and Development of an Integrated Corn and Corn Stover Ethanol Pathway in the GREET™ Model

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

Wang, Zhichao; Dunn, Jennifer B.; Wang, Michael Q.

Corn ethanol, a first-generation biofuel, is the predominant biofuel in the United States. In 2013, the total U.S. ethanol fuel production was 13.3 billion gallons, over 95% of which was produced from corn (RFA, 2014). The 2013 total renewable fuel mandate was 16.6 billion gallons according to the Energy Independence and Security Act (EISA) (U.S. Congress, 2007). Furthermore, until 2020, corn ethanol will make up a large portion of the renewable fuel volume mandated by Renewable Fuels Standard (RFS2). For the GREET1_2014 release, the corn ethanol pathway was subject to updates reflecting changes in corn agriculture and at corn ethanolmore » plants. In the latter case, we especially focused on the incorporation of corn oil as a corn ethanol plant co-product. Section 2 covers these updates. In addition, GREET now includes options to integrate corn grain and corn stover ethanol production on the field and at the biorefinery. These changes are the focus of Section 3.« less

Stover removal effects on seasonal soil water availability under full and deficit irrigation

USDA-ARS?s Scientific Manuscript database

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...

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

USDA-ARS?s Scientific Manuscript database

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

40 CFR 180.232 - Butylate; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... on the following food commodities: Commodity Parts per million Corn, field, forage 0.1 Corn, field, grain 0.1 Corn, field, stover 0.1 Corn, pop, forage 0.1 Corn, pop, grain 0.1 Corn, sweet, forage 0.1 Corn, sweet, kernel plus cob with husks removed 0.1 (b) Section 18 emergency exemptions. [Reserved] (c...

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

DTIC Science & Technology

2002-06-01

typical of dewatering equipment used in the utility flue gas desulfurization industry to achieve high gypsum solids concentrations commercially...experience in the flue gas desulfurization industry, 1998. 22 Letter to B. Bunner, Delta-T Corporation, Williamsburg, VA, from A. Bowser, Komline...see Figure 16). Flue gas from the combustor preheats the entering combustion air then enters a baghouse to remove particulates, which are landfilled

Coordinated development of leading biomass pretreatment technologies.

PubMed

Wyman, Charles E; Dale, Bruce E; Elander, Richard T; Holtzapple, Mark; Ladisch, Michael R; Lee, Y Y

2005-12-01

For the first time, a single source of cellulosic biomass was pretreated by leading technologies using identical analytical methods to provide comparative performance data. In particular, ammonia explosion, aqueous ammonia recycle, controlled pH, dilute acid, flowthrough, and lime approaches were applied to prepare corn stover for subsequent biological conversion to sugars through a Biomass Refining Consortium for Applied Fundamentals and Innovation (CAFI) among Auburn University, Dartmouth College, Michigan State University, the National Renewable Energy Laboratory, Purdue University, and Texas A&M University. An Agricultural and Industrial Advisory Board provided guidance to the project. Pretreatment conditions were selected based on the extensive experience of the team with each of the technologies, and the resulting fluid and solid streams were characterized using standard methods. The data were used to close material balances, and energy balances were estimated for all processes. The digestibilities of the solids by a controlled supply of cellulase enzyme and the fermentability of the liquids were also assessed and used to guide selection of optimum pretreatment conditions. Economic assessments were applied based on the performance data to estimate each pretreatment cost on a consistent basis. Through this approach, comparative data were developed on sugar recovery from hemicellulose and cellulose by the combined pretreatment and enzymatic hydrolysis operations when applied to corn stover. This paper introduces the project and summarizes the shared methods for papers reporting results of this research in this special edition of Bioresource Technology.

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

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.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Corn stover for biogas production: Effect of steam explosion pretreatment on the gas yields and on the biodegradation kinetics of the primary structural compounds.

PubMed

Lizasoain, Javier; Trulea, Adrian; Gittinger, Johannes; Kral, Iris; Piringer, Gerhard; Schedl, Andreas; Nilsen, Paal J; Potthast, Antje; Gronauer, Andreas; Bauer, Alexander

2017-11-01

This study evaluated the effect of steam explosion on the chemical composition and biomethane potential of corn stover using temperatures ranging between 140 and 220°C and pretreatment times ranging between 2 and 15min. Biodegradation kinetics during the anaerobic digestion of untreated and corn stover, pretreated at two different intensities, 140°C for 5min and 180°C for 5min, were studied in tandem. Results showed that pretreatment at 160°C for 2min improved the methane yield by 22%. Harsher pretreatment conditions led to lower hemicellulose contents and methane yields, as well as higher lignin contents, which may be due to the formation of pseudo-lignin. The biodegradation kinetics trial demonstrated that steam explosion enhances the degradation of structural carbohydrates and acid insoluble lignin. Copyright © 2017 Elsevier Ltd. All rights reserved.

Utilization of lignocellulosic polysaccharides

NASA Astrophysics Data System (ADS)

Fenske, John James

Lignocellulosic biomass represents a vast supply of fermentable carbohydrates and functional aromatic compounds. Conversion of lignocellulosics to ethanol and other useful products would be of widespread economical and environmental benefit. Better understanding of the behavior of different lignocellulosic feedstocks in fermentation protocols as well as catalytic activities involved in lignocellulosic depolymerization will further enhance the commercial viability of biomass-to-ethanol conversion processes. The relative toxicity of the combined non-xylose components in prehydrolysates derived from three different lignocellulosic biomass feedstocks (poplar, corn stover and switchgrass, or Panicum virgatum L.) was determined using a Pichia stipits fermentation assay. The relative toxicity of the prehydrolysates, in decreasing order, was poplar-derived prehydrolysates > switchgrass-derived prehydrolysates > corn stover-derived prehydrolysates. Ethanol yields averaged 74%, 83% and 88% of control values for poplar, switchgrass and corn stover prehydrolysates, respectively. Volumetric ethanol productivities (g ethanol lsp{-1} hsp{-1}) averaged 32%, 70% and 102% of control values for poplar, switchgrass and corn stover prehydrolysates, respectively. Ethanol productivities correlated closely with acetate concentrations in the prehydrolysates; however, regression lines correlating acetate concentrations and ethanol productivities were found to be feedstock-dependent. Differences in the relative toxicity of xylose-rich prehydrolysates derived from woody and herbaceous feedstocks are likely due to the relative abundance of a variety of inhibitory compounds, e.g. acetate and aromatic compounds. Fourteen aromatic monomers present in prehydrolysates prepared from corn stover, switchgrass, and poplar were tentatively identified by comparison with published mass spectra. The concentrations of the aromatic monomers totaled 112, 141 and 247 mg(l)sp{-1} for corn stover, switchgrass and poplar prehydrolysates, respectively. The woody and herbaceous feedstocks differed in both amount and type of aromatic monomers. The cellulases of Trichoderma reesei are the most widely studied for use in the depolymerization of lignocellulosics. The Trichoderma cellobiohydrolases CBH1 and CBH2 are traditionally categorized as exo-acting cellulases. A simple individual-based model was created to explore the potential effects of native endo activity on substrate-velocity profiles. The model results indicate that an enzyme with a small amount of endo activity will show an apparent substrate inhibition as substrate levels are increased. Actual hydrolysis studies using affinity chromatography-purified CBH2 preparations from three laboratories indicate that CBH2 has native endo activity, while CBH1 does not.

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

PubMed

Liu, Tongjun; Williams, Daniel L; Pattathil, Sivakumar; Li, Muyang; Hahn, Michael G; Hodge, David B

2014-04-03

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. 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. This work demonstrates that this two-stage pretreatment process is well suited for converting lignocellulose to fermentable sugars and biofuels, such as ethanol. This approach achieved high enzymatic sugars yields from pretreated corn stover using substantially lower oxidant loadings than have been reported previously in the literature. This pretreatment approach allows for many possible process configurations involving novel alkali recovery approaches and novel uses of alkaline pre-extraction liquors. Further work is required to identify the most economical configuration, including process designs using techno-economic analysis and investigating processing strategies that economize water use.

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

PubMed

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

2018-01-01

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

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.

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.

40 CFR 180.598 - Novaluron; tolerances for residues.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Cattle, meat 0.60 Cattle, meat byproducts, except kidney and liver 11 Cherry 8.0 Cocona 1.0 Corn, sweet, forage 16 Corn, sweet, kernel plus cob with husks removed 0.05 Corn, sweet, stover 50 Cotton, gin...

40 CFR 180.475 - Difenoconazole; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Canola, seed 0.01 Citrus, dried pulp 2.0 Citrus, oil 25 Corn, sweet, forage 0.01 Corn, sweet, kernel plus cob with husks removed 0.01 Corn, sweet, stover 0.01 Cotton, gin byproducts 0.05 Cotton, undelinted...

40 CFR 180.468 - Flumetsulam; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... following raw agricultural commodities: Commodity Parts per million Bean, dry 0.05 Corn, field, grain 0.05 Corn, field, forage 0.05 Corn, field, stover 0.05 Soybean 0.05 [58 FR 57967, Oct. 28, 1993, as amended...

40 CFR 180.477 - Flumiclorac pentyl; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... million Corn, field, forage 0.01 Corn, field, grain 0.01 Corn, field, stover 0.01 Cotton, gin byproducts 3.0 Cotton, undelinted seed 0.2 Soybean, hulls 0.02 Soybean, seed 0.01 (b) Section 18 emergency...

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

1.2.1.1 Harvest, Collection and Storage Quarter 3 Milestone Report

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

Wendt, Lynn M.; Smith, William A.; Cafferty, Kara G.

Single pass baling of corn stover is required in order to meet targets for the herbaceous biomass 2017 logistics design case. Single-pass pass stover harvest is based on the grain harvest and generally results in stover with a moisture content of 30-50% wet basis (w.b). Aerobic storage of corn stover with high moisture results in high levels of dry matter loss (DML), up to 25%. Anaerobic storage (ensiling) reduces DML to less than 5%, but additional costs are associated with handling and transporting the extra moisture in the biomass. This milestone provides a best-estimate of costs for using high moisturemore » feedstock within the conventional baled logistics system. The costs of three (3) anaerobic storage systems that reduce dry matter losses (bale wrap, silage tube, and silage drive over pile) are detailed in this milestone and compared to both a conventional dry-baled corn stover case and a high moisture bale case, both stored aerobically. The total logistics cost (harvest, collection, storage, and transportation) of the scenarios are as follows: the conventional multi-pass dry bale case and the single-pass high moisture case stored aerobically were nearly equivalent at $61.15 and $61.24/DMT. The single-pass bale wrap case was the lowest at $57.63/DMT. The bulk anaerobic cases were the most expensive at $84.33 for the silage tube case and $75.97 for the drive over pile, which reflect the additional expense of transporting high-moisture bulk material; however, a reduction in preprocessing costs may occur because these feedstocks are size reduced in the field. In summary, the costs estimates presented in this milestone report can be used to determine if anaerobic storage of high-moisture corn stover is an economical option for dry matter preservation.« less

40 CFR 180.658 - Penthiopyrad; tolerances for residues.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., subgroup 5A 5.0 Brassica, leafy greens, subgroup 5B 50 Buckwheat, grain 0.15 Canola 1.5 Corn, field, forage 40 Corn, field, grain 0.01 Corn, field, refined oil 0.05 Corn, field, stover 15 Corn, pop, grain 0.01 Corn, sweet, kernel plus cob with husks removed 0.01 Cotton, seed 1.5 Cotton, gin byproducts 15 Fruit...

40 CFR 180.448 - Hexythiazox; tolerance for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... dates specified in the following table: Commodity Parts per million Expiration/revocation date Corn, field, forage 2.0 12/31/10 Corn, field, grain 0.05 12/31/10 Corn, field, stover 2.0 12/31/10 Corn, sweet, plus cobs with husks removed (K+CWHR) 0.02 12/31/12 Corn, sweet, forage 6.0 12/31/12 Corn, sweet...

40 CFR 180.658 - Penthiopyrad; tolerances for residues.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., subgroup 5A 5.0 Brassica, leafy greens, subgroup 5B 50 Buckwheat, grain 0.15 Canola 1.5 Corn, field, forage 40 Corn, field, grain 0.01 Corn, field, refined oil 0.05 Corn, field, stover 15 Corn, pop, grain 0.01 Corn, sweet, kernel plus cob with husks removed 0.01 Cotton, seed 1.5 Cotton, gin byproducts 15 Fruit...