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Bioenergy Presentations

Enhanced Sugarcane Bagasse Conversion to Sugars by Ozonolysis and Liquid Hot Water Pretreatments

S. Bordignon, R. da Silva, E. Ximenes, H. Roos, M. Ladisch, 38th Symposium on Biotechnology for Fuels and Chemicals, Poster Session 1: Bioprocessing, Reactor Design, and Separations Technology; Pretreatment and Fractionation; Microbial Science and Technology; Molecular Engineering, Synthetic Systems Biology, Poster M68, April 25, 2016, Baltimore, MD, , 


Abstract: Cellulose hydrolysis is achieved by a complex multi-enzymatic system that works more effectively when hemicellulose, lignin and their derived compounds are decreased in lignocellulosic substrates. In order to achieve this, we studied a combined approach by combining ozonolysis with liquid hot water (LHW) pretreatment of sugarcane bagasse. Under these conditions there was a 100% increase in available cellulose accompanied by an 80% decrease in hemicellulose, and 40% of lignin was oxidized. The double-pretreated material was further hydrolyzed in 50mM Sodium Citrate Buffer pH 5.0 at 10% (w/v) of solids loading using Cellic CTEC2 and HTEC2 (0.9 mg protein/g glucan) at 50 C. HPLC analysis showed that more than 40 g/L of glucose was released after 96 hours of hydrolysis, reaching 59% of conversion of the glucan. Single pretreatments (ozonolysis and LHW) were also performed separately and both gave 21 g/L of glucose, respectively. We showed that LHW pretreatment helps to remove partially the oxidized phenols after ozone attack, and also to solubilize the hemicellulose portion under high temperature, resulting in a more accessible glucan to the enzymes. The resultant liquor contains about 30 g/L of xylose and a large amount of phenolics (2.28 mg/L of Gallic Acid Equivalent). Conversion in the presence of this liquor is only 8% due to the strong inhibitory effect of phenols and carboxylic acids present in significant amounts in this fraction. Combining ozonolysis and LHW pretreatments is effective in separating cellulose from lignin and hemicellulose in bagasse, thereby generating fractions rich in sugars and phenolic compounds.

Research Area: Bioenergy

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Mechanisms of Lignin Derived Inhibition in Hydrolysis of Pretreated Biomass at Low Enzyme Loadings

M. Ladisch, E. Ximenes, C. S. Farinas, Y. Kim, J. K. Ko, T. Kreke, 38th Symposium on Biotechnology for Fuels and Chemicals, Session 12: Enzyme Science and Technology II - Assays, Characterization and Application, April 27, 2016, Baltimore, MD, , 


Abstract: The recalcitrance of lignocellulosic biomass materials with respect to enzyme hydrolysis is caused by structural factors and the interrelated effects of enzyme inhibitors. While liquid hot water, dilute acid, steam explosion, ionic fluid or alkaline pretreatments result in high conversion, these are insufficient for achieving low enzyme loadings due to inhibition effects. The products of cellulose hydrolysis - cellobiose and glucose - are known to inhibit cellulases and beta-glucosidases, with lignin-derived phenolics amplifying the overall inhibition effects. Further, lignin exposed through pretreatment interferes with hydrolysis by adsorbing cellulases and beta-glucosidases. The combined effects result in a conundrum: increasing severity of pretreatment, whether by chemical addition or hydrothermal conditions, results in significantly enhanced enzyme hydrolysis but also requires higher enzyme loadings. Excess enzymes, i.e, high enzyme loadings, are therefore needed if high yields from pretreated lignocellulosic substrates are to be achieved. We report mechanisms by which lignin derived inhibitors negatively affect enzyme activity and show how the interactions between insoluble and soluble enzyme inhibitors mask the mechanisms involved in enzyme hydrolysis of pretreated biomass. The identity of the inhibitors and the manner in which these molecules interact with cellulases, hemicellulases and beta-glucosidases will be discussed, together with approaches that show how enzyme loadings of 1 to 2 FPU/g total solids (after pretreatment) are sufficient to achieve 80% hydrolysis. The current work utilizes results from our laboratory and other leading research facilities to define an integrated mechanistic framework for the complex interactions that both limit and enhance enzyme hydrolysis of cellulose.

Research Area: Bioenergy

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Bioabatement with Hemicellulase Supplementation to Reduce Enzymatic Hydrolysis Inhibitors

G. Cao, E. Ximenes, N. N. Nishols, S. E. Frazer, D. Kim, M. A. Cotta, M. Ladisch, presented at 37th Symposium on Biotechnology for Fuel and Chemicals, San Diego, CA, April, 2015, , 


Abstract: Bioabatement, using the fungus Coniochaeta ligniaria NRRL30616 can effectively eliminate enzyme inhibitors from pretreated biomass hydrolysates. However, our recent research suggested that bioabatement had no beneficial effect on removing xylo-oligomers which are strong inhibitors to cellulase. Here, we evaluated bioabatement with xylanase supplementation to mitigate potential enzyme inhibitors observed in corn stover liquors after pretreatment with liquid hot water at 10% (w/v) solids. Resuslts showed that cellulose conversion in the presence of 10% (w/v) LHW-pretreated liquor reached 70.5% and 57.4%, for conversion of Solka Flock cellulose and pretreated corn stover solids, respectively, after bioabatement and xylanase supplementation. These represent an increase of 21.6% and 17.6%, respectively, in comparison with non-treated samples. The squence in which xylanase and cellulase are added affects cellulose conversion, possibly as a result of competition between xylanase cellulase binding to xylo-oligomers. Replacement of xylanase using maleic acid treatment to hydrolyze xylo-oligomers yielded equivalent increases in efficiency of cellualse hydrolysis.

Research Area: Bioenergy

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Changes, Sustainability, Food, Energy: Topics in Agriculture

M. Ladisch, Purdue University Borlaug Summer Institute 2015, Purdue University, June 16, 2015, , 


Abstract: This lecture asks the question of how fossil and bio-energy supply and demand might change if the world were to experience a leveling off of birthrate, a decreasing demand for petroleum, and in increasing demand for food, feed, fiber, and bio-products accompanied by global climage change. This open-ended presentation will discuss possible roles of technology, societal changes, water availability, and economics in allocating resources for sustainable production of food and energy, and for achieving a higher standard of living on a global basis.

Research Area: Bioenergy

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Effect of Liquid Hot Water Pretreatment on Enzyme Loading and Hydrolysis of Hardwood

M. R. Ladisch, Y. Kim, J. K. Ko, T. Kreke, E. Ximenes, 2015 AIChE Meeting, Paper 775b, Salt Lake City, Utah, November 13, 2015, , 


Abstract: A fundamental understanding of the combined factors that impact recalcitrance in enzyme hydrolysis of pretreated hardwood explains how cellulase loading may be decreased by a factor of 10 while maintaining 80% glucose yield when non-catalytic protein is added to the enzyme. Factors that impact enzyme hydrolysis of solid biomass include the interaction of the cellulase and beta-glucosidase components with solubilized phenolic inhibitors and the enhanced accessibility of lignin as a consequence of pretreatment. While the added protein decreases overall specific activity of the enzyme, it also reduces cellulase adsorption on lignin, thus making more enzyme available for cellulose hydrolysis. Consequently, 15 and 1.3 FPU cellulase/g total solids both give 80% yield, with the 1.3 FPU loading approaching the enzyme levels usually associated with amylases in starch hydrolysis. These results reinvigorate motivation for the search for other approaches that prevent enzyme adsorption on lignin and enable high glucose yields at low enzyme loadings. This paper presents measurements in our laboratory and prior reports from the literature to offer an explanation of how changes in the physical attributes of cellulosic biomass during liquid hot water pretreatment affect glucose yields and enzyme loading.

Research Area: Bioenergy

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Effect of Phenolic Compounds Derived from Pretreated Sugarcane Bagasse on Cellulolytic Activities

M. Michelin, E. Ximenes, M. L. T. m. Polizeli, M. R. Ladisch, presentd at 37th Symposium on Biotechnology for Fuel and Chemicals, San Diego, CA, April, 2015, , 


Abstract: Lignocellulosic residues, such as sugarcane bagasse (SCB), are a complex matrix composed by cellulose, hemicellulose and lignin that can be used for different biotechnological applications. These materials need to be pretreated to be accessible for enzymatic hydrolysis. Liquid hot water (LHW) pretreatment is an effective and cost-saving approach, since no catalyst is required, and an expensive reactor is avoided due to the low corrosive nature of this pretreatment. However, during the pretreatment phenolics derived from lignin are released, which are inhibitory of enzymes. Here, we evaluated the effect of phenolic compounds formed during the pretreatment of the SCB on cellulolytic activity. Two conditions for LHW pretreatment were used: 180 and 200 C for 30 min and two fractions were obtained: solid and liquid fractions enriched by cellulose/lignin and hemicellulose, respectively. The phenolics contained in the liquid and solid fractions were used for the experiments of enzymatic inhibition (cellulase and beta-glucosidase activities). The higher amount of phenolics (2.4 g/L) was observed in the liquid fraction of SCB pretreated at 200 C/30 min. This condition also resulted in the highest inhibition of the enzymatic activity. Phenolics extracted from solid fraction (0.86 g/L) were shown to be more inhibitory than liquid for the beta-glucosidase activity. This work shows the importance of the optimization of the pretreatment process in relation to maximize the production of sugars and minimize the formation of inhibitory compounds to achieve the maximal efficiency of an enzyme hydrolysis-based process.

Research Area: Bioenergy

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Enzymatic Liquefaction of Corn Stover and Pericarp (Fiber)

D. Kim, N. Hengge, D. Orrego, E. Ximenes, M. R. Ladisch, 2015 AIChE Annual Meeting, Paper 257B, Salt Lake City, Utah, November 10, 2015, , 


Abstract: There are two sources of cellulosic feedstocks for corn to ethanol, dry grind facilities: corn pericarp (fiber) and corn stover. Both materials quality for D3 RINS (renewable identification numbers for cellulosic ethanol), and could be an attractive resource for re-purposing corn to ethanol facilities for producing cellulosic ethanol. This approach would employ mixtures of endo- and exo-cellulases, pectinases, xylanases, protease, beta-glucosidase, as well as other possible auxiliary enzymes to liquefy and/or hydrolyze the cellulosic substrates. Tests, both in our laboratory and other research centers have demonstrated successful conversion of pretreated corn stover and other lignocellulosic materials. Processes for conversion of pretreated cellulose-containing distillers' solids have been demonstrated and are being marketed. Reports on this technology, available in the literature, show that a $10 to $12 million capital investment enables a 6% increase in ethanol production in existing corn to ethanol plants. This process requires pretreatment prior to hydrolysis and fermentation of the cellulosic portion of the corn kernel. Reports by Scott, Wyman, Schell, Elander, Kumar, Saville, Lawson and others have discussed the impact of mixing and reactor configurations on increasing both rate and yield of enzyme hydrolysis of cellulose, and/or liquefaction of pretreated lignocellulosic biomass (corn stover and hardwood). One significant factor that impacts economic viability of cellulose ethanol is being able to process biomass at high solids concentration in order to reduce energy for heating and other processing steps and increase the concentration of the ethanol produced. We recently reported the liquefaction of steam-exploded (pretreated) sugar cane bagasse at concentrations of up to 300 g/L. We present here the impact of reactor operation on the liquefaction of untreated corn stover and pericarp (corn fiber), and compares this to our recently reported liquefaction of sugar cane bagasse. The objective is to prepare these materials in pumpable slurries, thereby simplifying subsequent hydrolysis procedures, and reducing the cost of equipment that would otherwise require introduction of solid materials into a pressure vessel (i.e., a pulping digester).

Research Area: Bioenergy

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Biomimetic Catalyst: Maximizing Yields of Hydroxymethylfurfural from Whole Biomass

B. B. Hewetson, A. Kreger, N. S. Mosier AIChE Meeting, Atlanta, GA, November 20, 2014, , 


Abstract: Achieving high yields of HMF requires effective hydrolysis, isomerization, and dehydration of glucose from cellulose. We report the use of a cellulose solvent (85% w/w phosphoric acid) to remove and then recover cellulose from several plant biomasses (corn stover, switchgrass, and poplar) and microcrystalline cellulose (Avicel). The resultant amorphous cellulose is subjected to a conversion process where maleic acid hydrolyzes the cellulose to glucose, AlCl3 isomerizes the resultant glucose to fructose, and both acid catalysts dehydrate the fructose to HMF in a single reactor bi-phasic reactor where HMF is continuously extracted into MTHF. The results confirm yields of HMF (35 to 40%) can be increased by cellulose dissolution in concentrated phosphoric acid followed by hydrolysis of the reprecipitated amorphous cellulose. The increase in HMF yields is dependent upon the type of biomass. The total sugar conversion (C5 and C6 sugars) from the whole intact lignocellulosic starting biomass reaches >90% in the best case.

Research Area: Bioenergy

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Effect of Maleic Acid on the Selectivity of Glucose and Fructose Dehydration and Degradation

X. Zhang, B. Hewetson, N. S. Mosier AIChE Meeting, Atlanta, GA, November 20, 2014, , 


Abstract: 5-hydroxymethylfurfural (HMF) and levulinic acid are platform chemicals for producing a variety of fuels and polymers. However, undesirable humic substances can be generated in substantial amounts, lowering the yields of desired products. We report the use of hydrochloric acid and maleic acid separately and mixed with a Lewis acid (AlCl3) to catalyze the process of glucose isomerization, dehydration, and hydrolysis. Analysis of results between 130 and 180 C were used to develop a kinetic model for the glucose conversion to HMF and levulinic acid by these selected catalysts. Preliminary results show that after 6 minutes at 180 C, maleic acid combined with AlCl3 generated only 50% of total humins compared to hydrochloric acid combined with AlCl3. We report an analysis of this shift in selectivity of the reaction toward levulinate and describe possible mechanisms for interactions between maleic/maleate and the reactants and intermediates.

Research Area: Bioenergy

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Effects of Lignin and Phenolic Inhibitors on Enzyme Loading

M. Ladisch, E. Ximenes, Y. Kim, J. K. Ko, BIO Pacific Rim Summit, San Diego, CA, December 8, 2014, , 


Abstract: This panel focuses on recent advances in leading pretreatment technologies that can be coupled with enzymatic hydrolysis to convert lignocellulosic biomass to sugars for fermentation to ethanol or other products. The low cost of lignocellulosic biomass coupled with widespread domestic abundance, ability to dramatically reduce greenhouse gas emissions, and potential to spawn new rural manufacturing jobs make it an attractive resource from which to produce fuels and chemicals. However, converting this low cost resource into commodity products is expensive, with recalcitrance to sugar release being the key obstacle to achieving low prices by biological conversion routes. Most forms of lignocellulosic biomass must be pretreated prior to biological conversion operations to realize the high yields vital to economic competitiveness, and effective pretreatments can also lower loadings of expensive enzymes to economic levels, reduce costs of downstream operations,and produce valuable co-products that can improve overall process economics and provide additional benefits. Various studies have shown that thermochemical pretreatments that employ chemicals in combination with heat are most effective in realizing high sugar yields from the coupled operations of pretreatment and enzymatic hydrolysis. This Panel will include a presentation of recent work at Purdue University on reducing the amount of enzyme required for hydrolysis and the fundamentals of pretreatment related to changes in cell wall structure and chemistry. Increased severity of pretreatment exposes both additional lignin and cellulose. However, lignin adsorbs cellulase, so more enzyme must be added if the additional exposed cellulose is to be effectively hydrolyzed. Conversely, cellulase loading may be decreased by a factor of 10 while maintaining 80% glucose yield by diluting the enzyme with non-catalytic protein (BSA) that binds to lignin and decreases cellulase adsorption on lignin. More enzyme is therefore available for cellulose hydrolysis resulting in enhanced hydrolysis. Michigan State University is advancing Ammonia Fiber Expansion (AFEX) pretreatment, now being commercialized, to produce cellulosic biomass that can be used either for animal feed or as biofuel feedstock, thereby largely eliminating the "food versus fuel" issue. The AFEX presentation will briefly describe AFEX science and technology and how it can be performed in distributed processing facilities called depots. These depots greatly improve the logistics of cellulosic biofuel systems and allow local communities to capture part of the added value of AFEX processing. A presentation by the University of California at Riverside will describe a novel Co-solvent Enhanced Lignocellulosic Fractionation CELF) pretreatment that removes nearly all the lignin from biomass, recovers most of the hemicellulose sugars, and produces glucan-enriched solids that can be almost completely enzymatically digested to glucose with about one tenth the enzyme loadings typically required. Furthermore, CELF has been found to be effective with a wide range of hardwoods, grasses, and agricultural residues. Following the fate of major biomass components, kinetic modeling and SEM imaging suggest that the high lignin removal afforded by CELF could play a key role in achieving such high sugar yields with extremely low enzyme loadings and lead to alternate strategies to improve pretreatment.

Research Area: Bioenergy

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Ozonolysis as a Pre-Pretreatment for Compacted Bioenergy Feedstock

I. Beheshti Tabar, P. T. Murphy, N. S. Mosier AIChE Meeting, Atlanta, GA, November 20, 2014, , 


Abstract: Ozone pretreatment has been shown to improve the enzymatic digestibility of cellulose. In this study, the chemical pretreatment of highly compacted switchgrass with ozone was carried out in a fixed bed reactor. Material density in the reactor, ozone concentration, and biomass particle size simulated large scale in-farm or conversion facility treatment of biomass bales. An industrially viable ozone concentration of 22.5 mg/l (15% w/w) was used to treat the samples for 24 hours. The results showwed that a significant amount of soluble sugars (about 10% of total sugars) was generated from ozone-catalyzed hydrolysis of the hemicellulose. Despite visible changes in color, compositional analysis showed no significant change in glucan content and insignificant changes in total lignin content after treatment. Nonetheless, digestibility of treated material increased by more than 5-fold. Enzymatic hydrolysis of the materials with a relatively low loading of 10 FPU/g glucan resulted in yields of glucose of 59% for water washed samples and 27% for unwashed, compared to 11 and 9% for non-treated samples, respectively. The significant improvement in hydrolysis yields for washed samples suggest that water-soluble inhibitors generated from lignin degradation may be present after ozone pretreatment.

Research Area: Bioenergy

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Feedstock Supply Pathways Influence Net Emissions from Biofuels

I. Emery, J. Dunn, J. Han, M. Wang, ASABE 2013, Kansas City, MO, July 24, 2013, , 


Abstract: Environmental assessments of biofuel production, including greenhouse gas inventories, rarely account for the full impacts of the feedstock supply chain. Dry matter losses, direct emissions of non-CO2 greenhouse gasses (CH4 and N2O) and material use in some feedstock production pathways can alter the emissions profile of cellulosic biofuels. Statistical distributions were fit to the frequency of reported losses during five biomass storage methods, including dry bales stored indoors, outdoors (covered), or outdoors (uncovered), bale silage, and bunker silage. Biomass losses during on-farm operations, handling, and transportation for each biomass format were integrated with expected storage losses into the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model, developed by Argonne National Laboratory. Direct emissions during anaerobic storage and plastic use for storage covers were also included for each relevant biomass pathway. Net greenhouse gas emissions from ethanol produced from switchgrass, Miscanthus, and corn stover increased by up to 9.8, 9.0, and 8.3 g CO2e/MJ, respectively, due to inclusion of dry matter loss in the biomass supply chain. Fossil energy use increased by up to 0.14, 0.13, and 0.14 MJ/MJ, respectively. Round bale silage had the greatest impact on greenhouse gasses and energy use. Bunker silage requires lower fossil energy use but results in similar levels of GHGs. Indoor storage minimizes all emissions and fossil energy use. Integration of supply chain pathways into GREET provides a novel and more accurate model of biofuel net emissions and allows side-by-side comparisons of multiple biomass supply chains for regulatory and environmental assessments.

Research Area: Bioenergy

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Impact of Feedstock Loss During Storage on Life Cycle Greenhouse Gas Emissions for Biofuel Production

I. Emery, N. Mosier, LCA XII, Tacoma, WA, September 25-27, 2012, , 


Abstract:

Research Area: Bioenergy

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Integrating Dry Matter Losses and Direct Gas Emissions During Biomass Storage Into Life Cycle Inventory Models of Switchgrass; and Miscanthus-Based Ethanol Production

I. Emery, N. Mosier, 34th Symposium on Biotechnology for Fuels and Chemicals, New Orleans, LA, April 30-May 3, 2012, , 


Abstract: Accurate estimates of greenhouse gasa emissions from biofuel production are necessary to ensure the economic and environmental sustainability of the biofuels industry and to meet government mandates for low-carbon fuel production. Biomass storage represents a critical gap in many biofuel life cycle assessment (LCA) methodologies, and may have a large impact on production and transportation logistics for biofuel feedstocks, in addition to greenhouse gas emissions. In this study, 143 laboratory-scale bales made from switchgrass and Miscanthus grown at Purdue University were stored in insulated boxes. Initial moisture content and bulk density were varied among the bales (11.8 - 34.2% w.b., and 103 - 308 kg/m3, respectively) and dry matter loss was tracked for each treatment combination over three months of storage. 22 additional laboratory-scale switchgrass bales at 9.9%, 14.1% and 18.6% moisture (w.b.) were stored at 4 C, 23 C, and 40 C under controlled aeration to monitor the direct emissions of the greenhouse gases CO2, CH4, and N2O during storage. Relationships between biomass moisture and rates of dry matter loss, and between moisture, temperature, and direct greenhouse gas emissions, were used to model the potential impacts of biomass storage on biomass supply logistics and net global warming potential of ethanol from switchgrass and Miscanthus at the biorefinery scale.

Research Area: Bioenergy

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Cellulosic Ethanol: Beyond Corn and Sugarcane

M. Ladisch and E. Ximenes, BECA, Medellin, Colombia, August 5, 2011


Abstract: Sugarcane and corn account for most of the world's current fuel ethanol production of 25 billion liters. Long-term growth of fuel ethanol and other biofuels will require utilization of the cellulosic feedstocks: wood, sugarcane bagasse, agricultural residues, and purposely grown energy crops such as switchgrass, energy cane and wood. These sources have the potential to substantially increase the amount of liquid biofuels, and especially cellulose ethanol, from fermentation processes, as well as to catalyze growth of new industries in Colombia and in the Americas. The rate and extent of adoption of cellulose-derived, lqiuid biofuels will depend on technology, feedstock availability, production costs, government policies and oil prices. Examples from emerging companies in the biofuels sector will illustrate how biotechnology is enabling the industry to evolve and produce both fuels and chemicals from renewable resources. This talk presents an overview of processes that are changing the world of biofuels, and moving the biofuels industry beyond corn and sugarcane.

Research Area: Bioenergy

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Maleic Acid Catalyzed Conversion of Hemicellulose to Furfural

N. S. Mosier, E. Kim, S. Liu, M. Abu-Omar , 2011 Annual Meeting of the American Institute of Chemical Engineers, Minneapolis, MN, October 18, 2011, , 


Abstract: Direct catalytic conversion of lignocellulosic biomass to biofuels could improve the carbon efficiency of biofuel production. We report the use of maleic acid, a dicarboxylic acid, to catalyze the fractionation of biomass into an aqueous solution of pentose (primarily xylose) and insoluble cellulose and lignin, followed by the conversion of the xylose to furfural under higher temperature and pressure. This method achieved 80-90% yield of xylose through hydrolysis of the hemicellulose from various biomass sources (switchgrass, poplar, pine) and achieved 54-61% yield of furfural (based on original biomass). We present a kinetic analysis of biomass hydrolysis and furfural formation and discuss application of results from pure sugars to results from biomass conversion.

Research Area: Bioenergy

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Sorghum and Switchgrass Storage Systems' Impact on Net Greenhouse Emissions from Cellulosic Ethanol Production

I. Emery, N. Mosier, 33rd Symposium on Biotechnology for Fuels and Chemicals, Seattle, WA, May 2-5, 2011, , 


Abstract: Life cycle assessment (LCA) of biofuel production is crucial in order to comply with regulations and to avoid or mitigate negative environmental impacts. Critical gaps in current LCA methodology, in particular a limited or absent consideration of biomass storage, may have dramatic impacts on net greenhouse gas (GHG) and other emissions. Our prior work shows that storage losses can increase the life-cycle GHG emissions of ethanol from corn stover by 20% to 100%. In this study, we examine the impact of multiple biomass storage and supply systems on life cycle GHG emissions from sweet sorghum and switchgrass grown in Tippecanoe County, Indiana. We assess potential dry matter losses, compositional changes, ethanol yield, and direct GHG emissions during storage of bales and silage in centralized and decentralized processing systems. Net emissions and energy use were calculated using the GREET model framework, into which we incorporated storage losses and direct emissions from biomass. Results highlight the impact of logistics, storage, and management decisions on the environmental impacts of second-generation biofuel feedstocks, and the potential benefits of dedicated energy crops for large-scale ethanol production.

Research Area: Bioenergy

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The Impact of Storage Parameters on Downstream Bioprocessing of Biomass

A. Athmanathan and N. S. Mosier, AIChE 2011, Minneapolis, MN, October 18, 2011


Abstract:

Research Area: Bioenergy

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Comparative Study on Enzymatic Digestibility of Upland and Lowland Switchgrass Varieties Processed by Leading Pretreatment Technologies

Y. Kim, N. S. Mosier, M. R. Ladisch, 32nd Symposium on Biotechnology for Fuels and Chemicals, Clearwater Beach, FL, April 19-22, 2010


Abstract: Variability in feedstock quality as a function of cultivar, production location, and harvest time may have significant impacts on enzymatic saccharifaction and biofuels production. The Biomass Consortium for Applied Fundamentals and Innovation (CAFI) has examined several leading pretreatment technologies applied toward processing switchgrass (Panicum virgatum L.). Switchgrass varieties can be categorized into two different ecotypes primarily based on latitude of origin: upland and lowland. Upland varieties are more adapted to cold temperature and semi-arid climates and tend to grow shorter and less coarse than low land types. Southern-origin lowland curtivars tend to grow taller and be more bunchy and thicker-stemmed, producing more biomass than upland types. In this study, we report comparative saccharification yields of three different varieties of switchgrass, two upland types (Dacotah and Shawnee) and one lowland type (Alamo) switchgrass harvested in the fall or in the spring after standing in the field over winter. Comparisons were also made among the types of switchgrass before and after processed by pretreatment technologies as part of the CAFI project (ammonia fiber expansion, aqueous ammonia recycle, dilute sulfuric acid, lime, and neutral pH liquid hot water). These comparisons are of data obtained through identical experimental protocols and data analysis techniques using common supplies of switchgrass. The key features of different types of switchgrass and the effects these differences had on hydrolysis performance for the applied pretreatment methods are discussed.

Research Area: Bioenergy

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The Influence of Dry Matter Loss During Biomass Storage on Net Greenhouse Gas Emissions During Ethanol Production from Corn Stover

I. Emery, J. Park, E. M. Sajeev, and N. Mosier, 32nd Symposium on Biotechnology for Fuels and Chemicals, Clearwater Beach, FL, April 19-22, 2010


Abstract:

Research Area: Bioenergy

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Comparative Study on Enzymatic Digestibility of Upland and Lowland Switchgrass Varieties Processed by Leading Pretreatment Technologies

Y. Kim, N. S. Mosier, M. R. Ladisch, 2009 AIChE Annual Meeting, Nashville, TN, Nov. 8-13, 2009


Abstract: Switchgrass (Panicum virgatum L.) is a promising dedicated bioenergy feedstock with numerous environmental benefits, due to its low fertility requirements, tolerance of poor soils and drought, and high biomass yield. Switchgrass varieties can be categorized into two different ecotypes primarily based on latitude of origin: upland and lowland. Upland varieties are more adapted to cold temperature and semi-arid climates and tend to grow shorter and less coarse than low land types. Southern-origin lowland curtivars tend to grow taller and be more bunchy and thicker-stemmed, producing more biomass than upland types. In this study, we report comparative saccharification yields of three different varieties of switchgrass, two upland types (Dacotah and Shawnee) and one lowland type (Alamo) switchgrass, pretreated by controlled pH, liquid hot water (LHW) pretreatment. Hydrolysis of LHW pretreated switchgrass at 15% w/v dry solids loading resulted in 80% glucose yield and 90% xylose yield at a total protein loading of 11 mg protein/g dry biomass where the total protein consists of cellulase combined with supplementary xylanase. Comparisons were also made among the types of switchgrass processed by other pretreatment technologies as part of the CAFI project (ammonia fiber expansion, aqueous ammonia recycle, dilute sulfuric acid, lime, and neutral pH liquid hot water). These comparisons are of data obtained through identical experimental protocols and data analysis techniques using common supplies of switchgrass. The key features of different types of switchgrass and the effects these differences had on hydrolysis performance for the applied pretreatment methods are briefly discussed.

Research Area: Bioenergy

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The Impact of Dry Matter Loss During Biomass Storage on Net Greenhouse Gas Emissions from Biofuels Production

Isaac Emery and Nathan Mosier, Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907 , 2009 ESE Symposium, September, 2009


Abstract:

Research Area: Bioenergy

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Apollo Program for Biomass Liquids - What Will It Take?

M. Ladisch, Richard Lugar Energy Summit, August 29, 2006


Abstract:

Research Area: Bioenergy

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Bio-energy at Purdue University

Ladisch, Michael, on behalf of an interdisciplinary research team from the Schools of Agriculture, Engineering and Science, IN- ATAIN Network Event, Alternative Energy Research, Purdue University, Stewart Center, West Lafayette, IN, September 28, 2005


Abstract:

Research Area: Bioenergy

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Bioenergy - Now and Forever

Ladisch, Michael, Seminar for Purdue's Electrical and Computer Engineering Class, ECE694, Purdue University, West Lafayette, IN, October 6, 2005


Abstract: The price of gasoline has attracted our attention to the nature of our economy, lifestyle, and use of liquid fuels. Currently, gasoline is expensive, but marketplace economics have prevented shortages. Now, imagine a world with gasoline at $100/gallon and oil at $2000/barrel. We would probably use more bioenergy - particularly liquid fuel obtained from plants, wind and solar sources. Since bioenergy is already available, would this scenario translate into an energy boom? How would our lifestyle change? The answers will reflect availability, sustainability, and the ability of agriculture to generate renewable feedstocks for use in producing liquid fuels. Efficient transformation of renewable solid forms of carbon into liquid transportation fuels will require metabolic engineering of yeast, advanced macromolecular or nano-scale catalysts, efficient separations technology and engineering of crops and microorganisms for industrial use. If bioenergy is to be used forever (or at least as long as the sun shines) sustainability becomes a key issue. The toolbox for building our energy future will include biology, mathematics, biocatalysis, and bioprocess engineering, as well as the tehcnologies: bio-, nano-, info-, and eco-. The ultimate impact of bioenergy will depend on how it is integrated into a global society, where sources and uses of energy are distributed both geographically as well as technologically. More nuclear, coal, solar, wind, shale oil, and methane hydrolytes, and less oil and less NIMBY will be part of the alternate energy portfolio. We will discover that the future of bioenergy is not only about alternate energy and tehcnology, but also about the role of engineers as leaders of societal change. Arguments in support of these hypotheses will be presented.

Research Area: Bioenergy

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