Samantha Austin, Graduate Student

Rhodobacter sphaeroides growth and substrate utilization in pretreated corn stover hydrolysates

Rhodobacter sphaeroides 2.4.1is a well-studied photosynthetic purple non-sulfur bacterium. It is a metabolically diverse organism that can grow via a variety of different lifestyles. In anaerobic photosynthetic growth conditions, R. sphaeroides has the potential to produce biofuels (hydrogen) and biofuel precursors (fatty acid lipids). We are investigating the ability of R. sphaeroides to grow in anaerobic photosynthetic conditions in pretreated corn stover hydrolysates and characterizing hydrolysate utilization by R. sphaeroides. R. sphaeroides growth is only observed in diluted AFEX pretreated hydrolysate, and adapted evolution of R. sphaeroides has only allowed for growth to occur in concentrations of 40% AFEX hydrolysate. Analyses of substrate utilization of R. sphaeroides indicate that glucose and xylose, the main components of hydrolysates, are not fully consumed, while acids, such as formate, acetate, and lactate, are readily consumed. To better investigate the characteristics of R. sphaeroides growth in the substrates present in AFEX hydrolysate, comparison experiments are being carried out by growing and adapting additional R. sphaeroides strains and Rhodopseudomonas palustris (another well studied photosynthetic bacterium) in AFEX pretreated hydrolysate, Synthetic Hydrolysate (SynH), and in Alkaline Hydrogen Peroxide (AHP) pretreated corn stover hydrolysate. These hydrolysate pretreatment and growth comparisons will give us a better understanding of substrate utilization, biohydrogen production, and possible growth inhibitors of these biofuel producing bacterium.

Phil Brumm, Chief Scientific Officer, C5*6

Biomass and Beyond – Enzyme Solutions

C5•6 was spun out in 2006 from Lucigen Corporation, a molecular biotechnology firm founded in 1998. C5•6 is the recipient and license holder, for industrial uses, of Lucigen Corporation’s proprietary technologies in gene cloning and genomics that enable the discovery and commercialization of novel enzyme-based products from previously inaccessible environmental microbes. C5•6 is directing this portfolio of enzyme discovery technologies to the development and production of high-value molecules and patentable processes for the food, bioethanol, advanced biofuels, biomedical and biorefining markets. The company is currently co-located with Lucigen in a 28,000-square-foot facility in Middleton, Wisconsin.  C5•6’s technology platform has been developed over the course of seven years and has utilized over $6 million in U.S. Government SBIR grants and private equity investment in that effort. The firm has 8 employees (3 Ph.D., 3 AS/BS scientists).

Dr. Yury Bukhman

GCAT: a web-based tool for modeling and summarizing microbial growth curves from high-throughput screening data

We present GCAT, a user-friendly online tool which analyzes microbial growth curves and extracts quantitative parameters such as specific growth rate, lag time etc. GCAT uses nonlinear regression to model trends in cellular density versus time. When used to analyze simple sigmoid growth curves, it performs comparably to model-free analyses in order to provide numeric results that can be easily used in further analyses. GCAT is robust to data sparseness, requiring as few as 11 sampling points per growth curve. These aspects of GCAT make it widely useful as a time-saving tool for the simultaneous analysis of large sets of microbial growth curves.

Shishir Chundawat, Scientist

Deconstruction of pretreated cellulosic biomass by engineered enzymes

Cellulose crystalline structure can be modified to a non-native form during thermo-chemical pretreatments to improve bioconversion to biofuels. This unnatural form of pretreated cellulose is more readily digestible by some enzymes. However, there is a lack of basic enzymology research carried out on this novel substrate and is thus the primary focus of our research. Here, we explore the interactions of various enzymes with pretreated cellulose to gain insight into the factors that impact cellulose deconstruction to fermentable sugars.

Sasikumar Elumalai, Assistant Scientist

Bioconversion of Manure Fibers into Ethanol after Combined Maceration and Chemical Pretreatment

In the present study, post-biogas digestion manure fibers were used for the potential production of fuel ethanol after combined maceration and chemical pretreatment. Sieve analysis of the manure fibers showed fiber sizes ranging from < 75 μm to 2.4 mm with a calculated number average diameter (DN) of 0.041 mm. Chemical analysis of the fibers yielded a composition of 40-44% carbohydrate, 31-33% acid insoluble klason lignin, 8% ash, and 13% solvent extractable material. The saccharification ability of the recovered manure fiber was measured and found to yield less than 6% of the theoretical sugar using cellulase (CTec2) and hemicellulase (HTec2) at 3.5% loading (w/w) after 60 h.  The low yields of the highly recalcitrant fiber were improved, using a simultaneous treatment with alkali (sodium hydroxide) and aqueous ammonia using a specially designed pin mixer (macerator). The pretreatment conditions were statistically optimized using central composite design experiments with 3 dependent factors (chemical loading, reaction temperature and time) and 3 different levels. Chemical loading and treatment temperature significantly affects the carbohydrate and residual lignin recoveries of the manure fiber (approx. 2-fold decrease in recoveries with the corresponding increase in severity). Maximum saccharification efficiency (> 30%) is achieved with the pretreated manure fiber using cellulase (CTec2) and hemicellulase (HTec2) at 3.5% loading (w/w) after 60 h. In conclusion, manure fibers represent a recalcitrant carbohydrate source, that can be improved for ethanol production using a combined mechanical and chemical pretreatment with aq. NH3 and NaOH. Supported by USDA BRDI Grant 2012-10006-19423.

Erica Diehl

Optimizing Ecosystem Service Tradeoffs Given Probability of Conversion to Perennial Bioenergy Crops

Perennial bioenergy crops provide different ecosystem services (food and fuel production, carbon sequestration, erosion control, nutrient cycling) from those provided by traditional row crops, and the delivery of these services is also variable based on location (soil type, topography, etc). Strategic placement of perennial bioenergy crops on the landscape can maximize ecosystem services, while minimizing opportunity costs. However, due to social and economic factors, not all land managers are equally willing to convert land to perennial bioenergy crops. We use a computer program to combine modeled ecosystem service data with survey-derived probabilities of conversion to find target areas where perennial bioenergy crops will provide the highest environmental benefit for the lowest economic cost.

Alison Ferris

Distillation Curve Optimization for the Volatility Characterization of Drop-in Gasoline Fuels

The performance of a gasoline blend can be characterized by its ability to vaporize under various conditions. Properties used to quantify the vaporization or volatility of a fuel include the fuel’s distillation curve, Reid Vapor Pressure (RVP), and temperature for a vapor-to-liquid ratio of 20 (TV/L=20), as specified by the ASTM standard, “Standard Specification for Automotive Spark-Ignition Engine Fuel,” or ASTM D4818. The current work uses a model to automate the process of finding drop-in green gasoline fuels (composed of chemical components derived from renewable, biological materials) with volatility characteristics similar to those of gasoline. Once the appropriate fuel blend components have been identified, the biofuel blends are mixed and their volatility properties are verified experimentally and compared to those of available gasoline blends.

Design Methodology of Bio-Derived Drop-In Gasoline Fuels

Previous work used a model to automate the process of finding drop-in green gasoline fuels (composed of chemical components derived from renewable, biological materials) with volatility characteristics similar to those of gasoline.  The current work explores the autoignition characteristics of these biofuel blends through laboratory engine testing.  Relevant parameters for matching gasoline performance in an engine include relative flame speed, combustion phasing, and engine knock.  These combustion characteristics were recorded for two biofuel blends and compared to a research-grade gasoline fuel.  Additional human and environmental health factors that were explored include emissions, toxicity, and water solubility.

Cliff Foster, Research Assistant

Cell Wall Analytical Facility - Detailed Compositional Analysis of Feedstock Materials

The Cell Wall Analytical Facility at Michigan State University is a medium throughput facility that offers detailed cell wall matrix composition analysis as a service to support GLBRC research projects.  Analyses include; matrix polysaccharide composition, crystalline cellulose content, total lignin content, and lignin monomer composition.  Over the years, the facility's workflow has become highly optimized for feedstock analyses with the addition of two custom made biomass milling and weighing robots (iWall and Pulverizer) and a custom designed LIMS for easier sample submissions, tracking, data reporting, and more secure data storage.

Mahlet Garedew, Graduate Student

Upgrading of Fast Pyrolysis Oil to Chemicals and Fuels via Electrocatalytic Hydrogenation

Fast pyrolysis is a thermochemical approach for biomass liquefaction in which biomass is heated without oxygen to produce pyrolysis gas and biochar. The majority of the pyrolysis gas can be condensed to bio-oil with a bulk density greater than the feedstock biomass. However, bio-oil corrosiveness and reactive instability pose significant barriers to the adoption of pyrolysis systems for liquid fuel production. Electrocatalytic hydrogenation (ECH) is proposed to stabilize bio-oil under mild conditions (25-80°C and 1 atm). The production of lignin, at either centralized or decentralized facilities, provides an opportunity for thermal and electrocatalytic approaches to produce even more liquid fuel. Deriving value from lignin is important as it accounts for 10-30 wt% of biomass and 40% of its energy. As lignin is converted to phenolic monomers, dimers, and oligomers upon pyrolysis, the transformation of model compounds exhibiting similar bonding arrangements indicates the potential for the ECH of biomass lignin. ECH of these compounds are carried out using a novel activated carbon cloth supported ruthenium cathode. The outcome of this research will be an advanced understanding of integrated pyrolysis-ECH systems for bio-oil stabilization.

John Greenler, Director of Education and Outreach, Great Lakes Bioenergy Research Center

Preparing bioenergy leaders and educated citizenry for today and tomorrow

The Education and Outreach (E&O) Area of GLBRC collaborates closely with bioenergy researchers to develop classroom materials; provide corresponding professional development for educators; and facilitate research experiences for undergraduates who are minority, low income or first in family to college. These efforts 1) use contemporary bioenergy research to allow students a greater understanding of the fundamentals of energy and matter, including flows, cycles and conservation; and 2) engage students in the contemporary integration of science and engineering practices. These efforts align with the recently released Next Generation Science Standards and corresponding Framework as developed by the National Academy of Sciences. E&O materials are primarily distributed through GLBRC's website, and education staff run presentations and workshops for audiences nationally.

Kate Helmich, Graduate Student

Homology models of two BAHD acetyl-transferase enzymes important in lignin biosynthesis

Lignin is a complex aromatic polymer in plant cell walls that is essential to their function. However, due to its cross-linking with other cell wall polymers and strong bonds between subunits, lignin is a major contributor to cell wall recalcitrance, inhibiting polysaccharide utilization. One strategy to overcome this hurdle is to introduce more easily cleavable ester linkages into the lignin backbone to allow for breakdown at lower temperatures and pressures (1). This is especially important in the biofuels industries where lignocellulosic biomass is a major source of polysaccharides for ethanol fermentation. Two enzymes in particular, feruloyl-CoA:monolignol transferase (FMT) and p-coumaroyl-CoA:monolignol transferase (PMT), have been identified which catalyze the acylation of monolignols, producing monolignol hydroxycinnamate ester conjugates (1). Here we report homology models of both PMT and FMT. Both models have the two-domain fold typical of the BAHD acyl-transferase superfamily with the proposed active site located in a solvent channel between the two domains. Both proteins have been expressed and purified in E. coli. While ongoing crystallization trials are being conducted these computational models will aid in the understanding and characterization of these enzymes for use in the biofuels industry.

Alan Higbee

Enabling the Science of Bioconversion of Plant Cell Wall to Biofuel: Analytical platforms for profiling inhibitors in lignocellulose hydrolysates, and understanding their effects on cellular metabolism

Research in the Great Lakes Bioenergy Research Center aims to identify and overcome the regulatory and metabolic bottlenecks associated with conversion of lignocellulosic biomass to liquid transportation fuels, such as ethanol and isobutanol. Hydrolysates prepared from AFEX-pretreated corn stover (ACSH) support robust growth of bacterial and yeast strains, and efficient conversion of glucose to ethanol. However, xylose conversion is much less efficient, the result of inhibitory compounds within ACSH that limit xylose conversion. To identify these inhibitory compounds we have developed an analytical platform for characterizing the composition of lignocellulose hydrolysates. This platform can quantify greater than 60 compounds known or suspected to be present in ACSH deriving mainly from the degredation of lignin and carbohydrates including acid, amide, aldehyde, ketone, and alcohol forms of variously substituted cinnamic acid derivatives , furan derivatives (furfural) and a series of hydroxy and methoxy substituted benzylic acids, amides, ketones, aldehydes, and alcohols, and common organic acids. Using this platform we have characterized the abundances of several know inhibitors and shown that different classes of compounds undergo very different metabolic fates during microbial fermentation. Furthermore, this work also enables the identification of unknown compounds present in ACSH, and efforts are underway to identify several highly abundant componnents revealed in our original analysis. To understand the mechanism by which inhibitory compounds in ACSH limit xylose conversion, we have developed a platform for quantifying intracellular metabolites. This platform allows quantification of 20/23 metabolites of glycolysis, TCA cycle, and pentose-phosphate pathways, as well as many of the cofactors needed for these pathways. Our results show that aromatic acids and amides in ACSH have strong inhibitory effects on glycolysis and pyruvate metabolism, and lead to profound changes in abundances of molecules associated with cellular energetics and redox. The improved molecular understanding of the composition of lignocellulosic hydrolysates and their effects on metabolism defines targets for strain engineering, which will lead to improved biocatalysists with improved conversion characteristics.

Steve Karlen

Misregulation of p-Coumaroyl-CoA:Monolignol Transferase in Brachypodium distachyon

Lignification in plants occurs via oxidative radical coupling from monolignols, mainly p-coumaryl alcohol (H), conerfyl alcohol (G), and sinapyl alcohol (S). The lignin of grasses contains a substantial amount of p-coumarate (pCA) as pendent group on the phenylpropaniod polymer backbone. Recently, the gene that codes for the production of p-Coumaroyl-CoA: Monolignol Transferase (PMT), the enzyme that couples pCA to monolignols H, G, and S, was identified in rice. To test the authenticity of PMT as an enzyme in the lignin biosynthetic pathway, we misregulated the putative BdPMT gene in Brachypodium distachyon. Through a series of complementary assays for quantitative characterization of pCA functionalization on lignin (DFRC) and on arabinoxylans (pCA-Ara analysis), the PMT enzyme was shown to be selective for the formation of pCA esters on monolignols in vivo. This conclusion is supported by 2D HSQC NMR spectral analysis of whole cell wall and cellulolytic enzyme lignin (CEL) samples of each genetic line. We will present our characterization of these misregulated PMT Brachypodium distachyon lines.

Sarah Krantz

The Effects of Biochar in the Reduction of Nutrient Leaching

Excessive application of nutrient rich fertilizers or manure to agricultural fields is a major contributor to water pollution. Specifically, due to excess fertilizer applications, nutrients can leach into ground and surface water, lowering water quality, creating algal blooms and even hypoxic zones in large lakes and oceans. This research investigates the addition of biochar, a carbon rich byproduct of pyrolysis, as a soil amendment to reduce fertilizer contamination into ground and surface water. Other research, has demonstrated biochar’s ability to sequester nutrients, but this phenomenon is not well understood. In this investigation, different forms of biochar were created by altering pyrolysis reactors, pyrolysis conditions, and the initial biomass feedstock. These samples were characterized in the laboratory anon their ability to sequester liquid fertilizer, along with traditional chemical and surface chemistry tests to better understand the nutrient sequestering mechanism. Additionally, confirmatory studies were performed by soil column testing with and without biochar amended soil. From these data, several hypotheses have been created to describe biochar’s utrient sequestering mechanism. Using these mechanisms, the research will inform future work to improve biochar’s ability to reduce unwanted leaching into grown and surface water and improve water quality.

Gina Lewin, Graduate Student

A phylogenetic-based, systems-analysis of biomass deconstruction in the genus Streptomyces

Herbivorous insects, such as woodwasps, pine beetles, and leaf-cutter ants, associate with diverse communities of microbes that are highly efficient at decomposing plant biomass. We have isolated and characterized novel lignocellulolytic microbes and enzymes from these systems.

Zong Liu

Value added dairy manure protein separation and utilization

With the decrease in the total number of dairy farms while the milk production continues to increase, the large size dairy farms are facing the issue of dairy manure treatment, solid utilization and water recycling. The conventional methods for dairy manure treatment have struggled with the problems such as low separation efficiency and high energy and capital cost. Dairy manure contains large quantities of lignocelluloses, polysaccharides, proteins, and other biological materials. With the proposed two-step dairy manure solid-liquid separation using polymer based technology discussed in this presentation, high protein separation efficiencies are possible with low cost. The physical separations were achieved using mild conditions such as non-adjusted pH and room temperature, and additionally the polymer based process has been designed for easy and safe operation. Comparisons of manure protein analysis have been studied. The separated protein from dairy manure was evaluated and the results showed its potential for uses such as industrial amino acids, bio-fertilizers, bio-fuel, plastic production and microbial growth medium. Furthermore, the recovered water was evaluated for the purpose of dairy barn flushing, irrigation and discharges which displayed a significant reduction in ecological risks and meet the government regulations.

Paul Meier

National Energy Modeling: Simulating long-term supply and demand for electricity, transportation and fuels

 

Research at WEI is building detailed forecasts of U.S. energy, then “plugging in” new technologies and ideas. Energy supply and demand is simulated for each U.S. State’s unique resources, infrastructure, rules & goals. National energy simulations are validated against historical performance and are multi-user networked, such that individual assumptions can be managed by subject-area experts. Through this work, we aim to assist communities and stakeholders who are visualizing and implementing “real-world” sustainable energy.

 

Oleg Moskvin

Merging Statistics and Biology: Downstream Analysis Assistant (DAA) pipeline

RNA-Seq technology has brought the potential of transcriptomic experiments to an entirely new level of accuracy and resolution that includes monitoring of condition-specific transcriptome rearrangement events. However, this potential remains largely unutilized because both statistical methods for RNA-Seq data analysis and algorithms of transcriptome assembly are still evolving actively. Development of algorithms and pipelines for extracting biologically valuable information from RNA-Seq experiments requires robust feedback loops between biology and statistics. To enable permanent dialogue between selecting and fine-tuning of the analytical methods, on one hand, and evaluation of higher-level results such as altered metabolic pathways, GO categories, regulons or other externally defined sets of genes (such as biclusters generated in a meta-analysis of public datasets), on the other hand, we have built an expandable automated pipeline that takes raw reads files and associated experimental conditions as input and creates a report on functional and regulatory patterns of response for all gene expression clusters. This includes generation of KEGG pathway maps colored by relative expression changes for all relevant comparisons and statistically confirmed changes. The pipeline is being used to evaluate the combinations of data processing algorithms at every stage of RNA-Seq data processing, from read mapping and expression level estimation to differential expression tests and gene clustering. Robustness of the biological patterns of response to choice of data analysis methods is used as a confidence measure to narrow down the list of discovered biological responses for subsequent experimental follow-up.

Kim Huong Pham

Accelerated Renewable Energy Consortium: Life Cycle Assessment

The Accelerated Renewable Energy project has indicated that, in addition to the production of fertilizer and biogas, manure has the potential to produce other biofuels like ethanol. The complex production of biofuels, including biogas, bioethanol and biodiesel, is possible for a dairy farm that is seeking to be energy independent. A key part of Maple Leaf operation is the manure separation system in which water is continuously recycled and the solid is separated to be used for the cow bedding. Every day about 1,250 cubic meters of water at 1.84 percent TS is recycled in the tower for manure flushing. For years, Maple Leaf has not needed to purchase bedding fibers for their cows. After supplying all necessary bedding, there are still 2,200 metric tons of extra fibers with 34-38% carbohydrate content which could be converted to ethanol (Elumalai, 2012). The nutrient balance in the manure is very important. During manure processing, it may lose nutrient value as it moves from system to system. Using information from the manure fact sheet, we calculated that for every metric ton of flushed manure at 4.46% TS, the N values are 0.84 kg to 1.44kg, depending on the time of incorporation, 0.72 kg of P2O5 and 2.04 kg of K2O. However, using X-Ray Florescence data from direct measurements at Maple Leaf Dairy farm, starting from the primary reception tank, we were able to observe how the nutrient values changed throughout the processing steps. The values of N, P, and K at this initial location were 9.68 kg, 2.71kg and 16.15 kg. The measurements of N, P, and K, from the DAF sludge which flows to the lagoon, were 2.81kg, 1.30kg and 3.73kg. This suggests that manure initially has a very high nutrient content but due to the process of storage, it loses its nutrient value. One major goal of this project is to address the environmental impacts of ethanol production at the Maple Leaf Dairy. Biofuels are considered to be environmentally mitigating fuels in comparison to fossil fuels, but the production ethanol on a dairy farm is complex and has never been done. Greenhouse gas emission from the manure is another concern, especially from the methane and nitrous oxide which contribute 21 and 310 times more to global warming than carbon dioxide. For these reasons, a life cycle analysis of Maple Leaf dairy model is necessary to determine if biofuel production can ultimately result in a more environmentally farm.

Gary Radloff, Director of Midwest Policy Analysis, Wisconsin Energy Institute

Developing a GIS-Based Decision Support Tool for Strategic Land Use Policy

Evaluating policy incentives for regional biofuels production systems with a scenario-based decision support tool.    Policy promoting bioenergy production must be compatible with the production of food, feed, fiber, and other valuable ecosystem services, such as climate regulation, water quality regulation, and biodiversity support. Public policy involves tradeoffs, and policymakers face the difficult challenge of understanding the relative value of these tradeoffs to achieve multidimensional goals.  This challenge is exacerbated by a lack of easy-to-use, spatially-explicit tools for policy evaluation.    This project will yield a novel, user-friendly decision support tool (DST) that will allow policy analysts to evaluate the effects of bioenergy policies (including subsidies, standards, mandates, tax credits and agricultural assistance programs) on a range of sustainability criteria in geographically-explicit fashion.  Sustainability criteria will include multiple environmental (e.g., soil carbon, nitrogen and phosphorus loss, biodiversity support), social (e.g., job creation, median income), and economic (e.g., producer income, tax revenue) metrics.      Researchers will work closely with a diverse team of regional stakeholders (farmers, state regulators, industry, conservation groups, federal agencies) and hold a series of public meetings to review the development of these tools and to evaluate promising policy scenarios.  Designing and assessing policy options in a place-based, participatory context will increase the likelihood of stakeholder acceptance, and the probability of attaining regionally-appropriate sustainable bioenergy systems.

John Ralph, Professor

Introducing Readily Cleavable Bonds into the Lignin Backbone: The Zip-Lignin™ Strategy

Lignin remains one of the most significant barriers to the efficient utilization of cellulosic substrates, in processes ranging from ruminant digestibility to industrial pulping, and in the current focus on biofuels production. Up- and down-regulating genes for enzymes in the monolignol biosynthetic pathway can produce at times striking alterations in lignin composition and structure that may positively or negatively impact a given processes. A few approaches hold considerable promise for reducing the severity and energy demands of various processes. At the same time, we are gaining some insight into what features are required by ideal lignin monomers and are beginning explorations into possible lignin monomer replacements. And now that monomer substitution in the lignification process is well authenticated in various transgenic plants, it is opportune to begin explorations into actually designing lignins to improve the ease with which they can be removed from the cell wall. Here we highlight one promising approach, the idea of utilizing monolignol conjugates to introduce readily (industrially) cleavable bonds into the backbone of the polymer. Model-cell wall studies showed dramatic improvements in processing efficiency, reducing the temperature required for pulping, for example. Successfully engineering plants to incorporate such monomer conjugates, or other monomer replacement strategies, therefore has the potential to vastly reduce the energy demands of processing. The poster will describe the latest results suggesting that this approach is likely to be successful!

Aicardo Roa-Espinosa

Accelerated Renewable Energy Consortium: Production of Granulated Bio-nutrients from Dairy Manure

The goal of our demonstration project is to develop and optimize innovative technology for the granulation of manure solids of customized nutrient content on site so that dairy farmers can produce nutrient-rich bio-fertilizers that will reduce current limitations associated with the transport and land application of manure. Also the conversion to bio-fertilizer creates a new source of revenue for the dairy farmer. We describe a process whereby fiber and protein isolated from air-dried manure are ground to less than 500 micron size and fed to a paddle macerator. The granulation process is optimized to yield maximum recovery of 2-3 mm sized granules by adjusting the moisture content of the feed, the feed volume, the amount of binder (Soil NetTM Polymer), and the rotational speed of the macerator. The granules produced by this process are more hydrophilic than raw manure, which prevents nutrient loss through surface and subsurface flows during rain/irrigation events. Our preliminary trials indicate that loading the macerator with a seed granule to one-fifth of its total volume, spraying 5% solution of Soil NetTM polymer, and running the paddle mixer continuously at 60 rpm results in a 70% yield of manure granules 3.17−1.18 mm in size. We also studied the parameters of the effective granulation process desired in manufacturing bio-nutrient granules at industrial scale.

Nicholas Santoro, Research Assistant

Platforms for Analyzing Biomass Cell Walls

The GLBRC Cell Wall Facility has implemented a number of diverse platforms for analyzing the cell wall of biomass feedstocks. This includes a high throughput platform (HTDP) for analyzing the cell wall digestibility of feedstocks for biofuels. The HTDP’s flexibility allows us to vary both the pretreatment and digestion conditions resulting in increased sensitivity for identifying plant genotypes that pretreat and saccharify more efficiently. In addition, the HTDP has been modified and expanded to allow us to also determine levels of non-structural carbohydrates in the biomass represented by free glucose, sucrose and starch. We also have experience handling and analyzing a variety of biomass feedstocks on the HTDP, including corn stover, switchgrass, miscanthus, poplar, Brachypodium, Arabidopsis and rice.

Jason Schatz

The urban heat island in Madison, Wisconsin

Urban heat islands (UHIs) are regions of elevated temperature created by built environments. UHIs have been observed from the Arctic circle to the tropics in cities ranging in population from a few hundred to tens of millions. Over 50% of the global population currently live in urban areas, meaning that UHIs affect the daily lives of over 3.5 billion people, a number expected to grow substantially over the coming century. The goal of our study is to characterize the patterns, drivers, and impacts of the UHI in Madison, WI, including its implications for health, resource consumption, and quality of life. To do this, in March 2012, 135 Onset HOBO® U23 Pro v2 temperature & relative humidity (T/RH) sensors were installed on light and utility poles across the Madison, WI area. The loggers were installed at a height of 3.5m and collect data every 15 minutes. Six additional loggers were installed in Oct 2012 and another ten in Aug 2013 for a total of 151. Results from the first full year of temperature data will be presented, including spatial patterns and daily and seasonal variation across the Madison area. The urban landscape has significant effects on temperature, with average nighttime temperatures in the urban core averaging 4-6C higher than rural areas during much of the year. Additional preliminary results also will be described.

Glen Stanosz

Screening poplar clones for resistance to Septoria canker disease, a factor limiting short-rotation, intensive-culture poplar feedstock production

Septoria canker disease causes growth loss and mortality of hybrid poplars, and epidemics in plantings of susceptible clones have limited adoption of short-rotation intensive-culture poplar production for bioenergy or biochemical feedstock. The potential to predict long-term canker disease damage to poplars by responses to inoculation with the fungal pathogen Septoria musiva has been demonstrated, but screening is not yet routine. To test validity of screening procedures, 15 clones of commercial interest to a forest industry cooperator (including resistant and susceptible standards) were inoculated during their first season of growth in the field. On each stem, the fourth or fifth fully expanded leaf was removed and an agar plug colonized by an aggressive isolate of S. musiva was placed over the resulting wound. Four months after inoculation, canker incidence, canker length, and percent of stem circumference affected (girdle) were recorded. Resulting cankers resembled those attributed to S. musiva and responses of standards were consistent with those previously reported. Clones varied greatly in canker incidence (17-96%), mean canker length (5-55 mm), and mean girdle (10-91%). Logistic regression analysis was used to compare responses with canker disease damage categories assigned on the basis of information from longer-term field studies. Incidence, canker length, and girdle data all were informative, and for most clones there was a high probability that responses to inoculation correctly predicted assigned canker disease damage categories. These results validate previous work indicating the feasibility and benefit of screening juvenile poplar clones for responses to inoculation with S. musiva before extensive field trials and release to growers.

Aniruddha Upadhye

Production of drop-in fuels and chemicals from aqueous hemicellulose stream

Hemicellulose is one of the major components of biomass consisting of oligomers of C5 sugar. It can be easily separated in the form of aqueous stream from the lignocellulosic biomass using a pretreatment process. This aqueous hemicellulose stream is also a by-product of pulp and paper industry. The focus of this presentation is a four step catalytic process for conversion of aqueous hemicellulose stream obtained from the pre-treatment processing. First, the oligomers of C5 sugars in hemicellulose stream (mainly xylose) are hydrolyzed and dehydrated to furfural in a continuous flow reactor with a homogeneous acid catalyst and a biphasic reaction scheme with tetrahydrofuran (THF) as co-solvent.  Furfural yields up to 90% were obtained in this first step. In order to be blended into jet/diesel fuel, we need precursors with higher carbon atoms. Thus, furfural is then condensed with acetone to form a C13 precursor in a biphasic base catalyzed aldol condensation reaction. The C13 precursor is then hydrogenated over Ru/C catalyst at low temperatures to saturate the double bonds. This low temperature hydrogenation makes the C13 precursor more stable towards high temperature hydrodeoxygenation step. In this step, certain larger oligomers are also formed from partially hydrogenated product. The product of hydrogenation step is subsequently hydrodeoxygenated over Pt/SiO2-Al2O3 at higher temperatures to obtain jet fuel range straight chain hydrocarbons. Using this process, we can produce hydrocarbons containing up to 31 carbon atoms. We have successfully demonstrated this process with aqueous hemicellulose stream obtained from real biomass. Here, we present our results on the demonstration of this process with aqueous hemicellulose stream derived from real biomass feedstock and provide directions for future research in catalytic conversion of hemicellulose component in biomass.

Kaitlin Whitney

Plant stress, pest control, and people: impacts of climate change and farmers' management on food, fuel, and food webs

Our work is on climate modeling and food web ecology in agroecosystems across the Midwest to better our understanding of how bioenergy related land use change is affecting insects, crop yields, and people.

Carol Williams, Research Scientist

Cross-sector collaborative development of anaerobic digestion for biogas production and native grassland restoration

Researchers at University of Wisconsin-Madison have with U.S. Fish and Wildlife Service jointly initiated a landscape-scale biomass harvest experiment. The experiment is the basis for understanding whether harvest of diverse perennial grass communities fulfills wildlife habitat management goals; feasibility of diverse end-uses of harvested materials; and formation of local value chains. Building upon the experiment, core collaborators from industry, agribusiness, and research have initiated a collaborative process to achieve multiple objectives including: location of an anaerobic digester that uses perennial grass biomass; exploration of landscape configurations of perennial grass production and alternative supply chain scenarios; understanding effects on existing markets of animal bedding and conventional haying; establishing system monitoring protocols; and formulation of adaptive responses to knowledge gained over time. While the challenges are many, essential progress has been achieved in commitment among collaborators, identification of shared values, and the formation of a strategic plan.  Future goals include partnership with a dedicated energy off-taker and engagement with a wider stakeholder group.

Zhouyang Xiang

Production of Furfural from Dried Distillers’ Grains: An Economic Point of View

Finding additional utilization for Dried Distillers’ Grains (DDG), a byproduct of corn ethanol production sold mainly as animal feed, has the potential to increase the value of DDG and thus can further decrease the cost for corn ethanol. Hemicelluloses are abundant in DDG but are underutilized since the major component in animal feed is protein. The pentoses of hemicelluloses have the potential of being converted into furfural. In this study, however, by economic analysis, merely producing furfural would not make DDG more profitable. Therefore, a two-step process, dilute acid extraction followed by dehydration of hydrolysate, is proposed to convert DDG into furfural, and the animal feed value of the remaining part of DDG needs to be considered. From the experiments, the optimum condition of dilute acid extraction of pentose from DDG was determined through full factorial experiment designs with central points at different levels of temperature, reaction time and acid concentration. A scaled up dilute acid extraction with better mixing of liquid and solid phase during reaction was conducted thereafter, and yield of 75% was achieved. The animal feed value of the solid residue from the extraction was evaluated. The hydrolysate was then converted into furfural by a conventional Batch method and a novel Batch Reactive Distillation (BRD) method. High yields in excess of 60% for furfural from BRD method were achieved. Using this data, an economical model was built to demonstrate the economic feasibility of this pentose extraction and dehydration process for corn ethanol producers.

Dr. Yaoping Zhang

Integration of lignocellulosic hydrolysate production, fermentation, omic data analysis, and microbial system biology to identify barriers in the conversion of lignocellulosic biomass to biofuels

A primary interest of the Great Lakes Bioenergy Research Center (GLBRC) is to identify, understand, and overcome regulatory and metabolic bottlenecks in the microbial conversion of plant biomass into biofuels. We have developed standard operation protocols (SOPs) for generating lignocellulosic hydrolysate from AFEX-pretreated corn stover (ACSH), and then used it in highly sensitive and informative systems biological approaches (e.g., “multiomic fermentation”). We also have generated a chemically defined synthetic hydrolysate that largely replicates the properties of ACSH to study the effect of lignocellulose-derived inhibitors (lignotoxins or LT) on the fermentation performance of ethanologen.