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1. Plant diversity in Brazil and potentialities for biodiesel production
Antonio Salatino
Although Brazil holds the world’s widest plant diversity, most plant species exploited in the country are exotic. This is true also regarding biodiesel production, a large proportion based currently on soybean (an exotic species) oil, with a strong trend in the short run to start production of jatropha (another exotic species) biodiesel. Several plant groups with high percentages of oleaginous members are well represented in Brazilian flora, such as Arecaceae and Euphorbiaceae. It is intended in this presentation to discuss characteristics of the Brazilian flora, regarding production of seed oils, their chemical composition and bearing on the production of biodiesel.
2. Synthesis of polysaccharides in the Golgi apparatus: The role of nucleotide sugar transporter and their role in modifying the structure of the cell wall
Ariel Orellana
Non-cellulosic polysaccharides are made of different sugars, which are assembled into polymers in the Golgi apparatus. Most of the enzymes involved in this process are located in the lumen of the Golgi apparatus; therefore, the nucleotide sugars, substrates of these enzymes need to be available in that compartment. Nucleotide Sugar Transporters (NSTs) are membrane proteins that are involved in the import of these substrates. They are encoded by genes which have different pattern of expression. Their substrate specificity change among them. Mutations in some of these genes may lead to an alteration in the synthesis of polysaccharides. Thus, they may be potential targets in order to modify the cell wall structure such that its properties may change.
Supported by Fondecyt 1070379, PCB-MN ICM P06-065-F, PFB-16
3. Species, genotype, and agronomic management effects on biomass yield and properties in Ontario, Canada
Bill Deen
In the province of Ontario, Canada, biomass markets are emerging for conversion via combustion and gasification systems. A series of research projects have been initiated across the province to evaluate both dedicated crops and agricultural residues for suitability of use in these markets. Perennial C4 grasses, including Miscanthus, switchgrass and big bluestem are the main dedicated crops being considered. Corn stover, soybean straw and cereal straw are the primary agricultural residues. Results indicate that yield and biomass are influenced by species, genotype, agronomic management and their interactions. For example, in a factorial experiment with four Miscanthus genotypes grown at four nitrogen rates and harvested in late fall and early spring, main effects and interactions were significant for yield, nutrient content and moisture levels. Yield and biomass quality are often negatively correlated and such tradeoffs must be considered when developing these biomass systems.
4. Designing Systems for Sustainable Production of Food and Fuel: Implications for Plant Scientists and Chemical Engineers
Bruce E. Dale
It is widely believed that food production and biofuels are in conflict and that increased biofuel production will lead to environmental degradation. This may be correct if biofuel production is imposed on a static agricultural system. But agriculture and the associated biofuel processing systems can be designed to meet demands for food and biofuel production while also providing large environmental services. This presentation explores several opportunities for sustainable biofuel production while meeting existing demands for food production. Implications for the plant sciences are discussed. Plant scientists and chemical engineers have a great opportunity to work more closely in designing and implementing sustainable biofuel systems.
5. Production of ethanol using bark residues from commercial eucalyptus plantations: challenges and perspectives
Carlos A. Labate
Commercial Eucalyptus plantations in Brazil are highly productive, having an average productivity of 41 m3 ha-1 year-1. Bark residues represent around 12-20% of the total biomass produced. On average, at the end of 7 years of cultivation the total biomass produced is around 150 tons ha-1 (20% wood water content), when the tree is harvested. From this biomass, bark represents around 17-25 tons ha-1, which is left in the field after harvesting, for nutrient recycling. The analysis of carbohydrate composition from barks of 5 different commercial clones of eucalyptus showed a wide variation in the contents of soluble sugars, with two clones showing an average of 5-10% of dry weight of sucrose. We are proposing a three step process to release the maximum amount of fermentable sugars, consisting on the first step the removal of soluble sugars, followed by a low acid pre-treatment to remove most of the extractives, lignin and pentoses (mainly xylose) and then an enzymatic attack of the remaining cellulose. Using such approach we have being able to produce ethanol with an efficiency around 85%.
6. Local Biomass... Local Opportunity
Dean W. Tiessen
I will outline Pyramid Farms experiences over the past few years in the procurement and productionf biomass. How this changed Pyramid Farms core business of greenhouse vegetable production, as well as how it will change others in this market. Moving from this to the identification of local opportunities in various markets and how to empower local feedstock supply chains within the agricultural community utilizing their own infrastructure, complimenting their core businesses. Biomass is a local initiative due to many factors one being land access. The agricultural community has invested in this for generations and is positioned well to be a major influence in this market. Having a new crop and cropping system will diversify a farmers portfolio and possibly allow them to participate further down the value chain in the production of new products and services.
7. Tapping the Natural Variations and Adaptability of Duckweeds (Lemnaceae) to Create a Bifunctional Platform for Wastestream Remediation and Biofuels.
Eric Lam
Duckweeds are aquatic plants of the Lemnaceae family that have adapted to most parts of the world with fresh to brackish water. They are the smallest flowering plants on earth and have the highest growth rate, with doubling time as short as 20 hours. Their natural ability to grow avidly on waterways and lakes with high nutrient levels has resulted in the use of these plants for wastestream remediation as well as environmental monitoring. Recently, duckweeds have also been shown to possess the potential for biofuel production using wastewater streams and sunlight to provide the necessary nutrients and energy, respectively. We have recently established the Rutgers Duckweed Stock Collective to preserve and maintain over 580 strains of duckweed that have been collected by Elias Landolt and others over the past 50 years. In this presentation, I will describe our efforts to begin to systematically characterize selected strains in our collection for natural variations in growth rates, chemical composition and biofuel feedstock potential. We believe the preservation and broad distribution of these materials, together with their detailed study at both the phenome and genome levels will contribute to our understanding of how plants such as duckweed can adapt to large ranges of climate variations. In addition, these studies should provide valuable information for choosing the optimal duckweed strain to deploy as a bifunctional platform for bioremediation and sustainable biofuel generation.
8. QTL Mapping in Sugarcane
Antonio Augusto Franco Garcia
QTL mapping is useful to help understanding the genetic architecture of quantitative traits in sugarcane, such as yield, fiber and sucrose content, providing the basis to marker assisted selection. However, it is necessary to develop new statistical approaches to analyse modern molecular data, since the current ones are just adaptations of methods developed for inbred-based populations, such as F2 and backcrosses. For species without inbred lines QTL mapping is in general conducted using full-sib families, where each locus can have different segregation patterns and linkage phases. In this talk new statistical approaches for QTL mapping in full-sibs and sugarcane will be presented, based on composite interval mapping and multiple interval mapping. Results showing their advantages over the pseudo-testcross strategy will be presented and discussed, showing that using such models could provide usefull information about additive and dominance effects, with more statistical power. The advantages of multipoint maps will also be discussed.
9. The FAPESP BIOEN Research Program: improving biomass, ethanol technologies and sustainability of the biofuel industry
Glaucia Mendes Souza
To respond to the increasing need in R&D in the biofuel area the State of São Paulo Research Foundation (FAPESP) created a Bioenergy Program (BIOEN). FAPESP is one of the Brazil´s leading public funding agencies for Scientific Research. The FAPESP Bioenergy Program BIOEN aims at articulating public and private R&D, using academic, research institutions, and industrial laboratories to advance and apply knowledge in fields related to ethanol production.
The BIOEN Program mission is to foster comprehensive academic and industry research on sugarcane and other biofuel sources integrated with the sugar and ethanol Industry, thus assuring Brazil’s position among the world leaders in Bioenergy research and industry. The research agenda includes biomass production and processing, biofuel production, engines and the overall impact on land use and on socio-economics aspects. The BIOEN Program is built on a solid core of academic research related to biomass production and processing, biofuel production, engines and impact on land use and socio-economic matters. It is expected that these activities will be translated into new knowledge and training of scientists and professionals for advancing industry in ethanol related technologies. Moreover, the BIOEN Program establishes partnerships with industry for cooperative R&D activities with public laboratories at universities and research institutes co-funded by FAPESP and industry.
10. How Much Cane We Expect of theTransgenic Sugarcane?
Helaine Carrer
Sugarcane is one of the main crops planted in Brazil and presents significant socio-economic and agribusiness importance to the country. The world scene is quite favorable as regards the marketing of its two main products, sugar and alcohol, driving the development of the national sugar-alcohol sector. Recently, there is increased interest in this crop especially due to the need to decrease fossil fuel usage. The need of increasing ethanol production for the maintenance and increase of agribusiness in the sugarcane agroindustry will demand expansion of area of production and adapted new varieties. Genetic breeding appears as the fundamental base for developing new varieties The complexity of sugarcane genome being aneuploidy and polyploidy, plus their relatively narrow genetic base impose great difficulties to the traditional breeding programs. According to this, genetic engineering techniques, such as nuclear and plastids genetic transformation are able to provide excellent alternative proceeding. Genes related to water stress tolerance, disease resistance and improving sugar content and also increase fibers are the main targets for improving sugarcane. Although transgenic sugarcane the technology has been shown since 1992 by biolistic approach no commercial variety was released until now. During this symposium challenges and mechanisms to improve the technology will be discussed.
11. Overview in Biofuels Research in Brazil
Marcos Buckeridge
The analysis of the energy sources of Brazil compared with the rest of the world shows clearly that the Brazilian energy system is distinctly directed to use biomass, having thrice the proportion of the world average. Ethanol from sugarcane, for instance, represents 16% of the energy sources. The use of ethanol as a source of energy for liquid fuel in Brazil is not new, as it has been produced since the 1930s, when ethanol from sugarcane was sold as a liquid fuel for transportation in the Northeast of the country. This initiative was dumped by the intense use of oil in the world up to the 1970s, when the rise in the price of oil led Brazil to establish the proalcohol project, a plan that led to the production of automobile engines that used ethanol alone as a fuel. The proalcohol demanded intense scientific and technological research in Brazil in several areas, from agricultural traits of sugarcane, up to development of engines, transportation logistics, to name but a few. There was even initiatives to develop cellulosic ethanol (the second generation) by use of acid hydrolysis at that time. Ethanol transiently lost the fight against oil again in the 90s and as the 21st century started with the rapid growth of developing countries, the demand led once again to an increase in oil prices. Of the same importance is the realization that Global Climatic Changes really impose a threat to humanity and that changing the way we use energy would be one of the ways to help to improve our environment in the future. As a result, due to the long tradition of Brazil in the research and use of ethanol as a liquid fuel, the country can be considered as having one of the cleanest energy matrices in the planet. In order to improve even more this position, States and the Federal government of Brazil are investing in research programs that intend to reinforce the science basis for bioenergy technologies. Three main actions have been established between 2007 and 2009. They are the BioEn program, founded by FAPESP (Foundation for Support of Science of the State of São Paulo), the Center of Science and Technology of Bioethanol, a federal center located in Campinas and the National Institute of Science and Technology of Bioethanol (INCT-Bioethanol), a joint effort of the Federal government and the State of São Paulo. EMBRAPA also created a new research center in Brasilia (EMBRAPA Agroenergy), which will have bioenergy as its primary focus of research. The federal government also created the Ethanol Network that congregates scientists developing research in bioenergy. Thus, it is quite clear that the primary research focus in Brazil is on sugarcane and ethanol. The main target is to improve crop productivity by understanding how plants produce sucrose and how the environment affects these mechanisms. Researchers want to genetically improve sugarcane beyond what has been done so far. To achieve this goal we are going to have the complete genome sequence of sugarcane and with this information in hands, find ways to improve sugarcane using tools as systems and synthetic biology. The second generation is a clear target for several researchers in this Brazilian Bioenergy Research Network. The goal is to find efficient mechanisms to degrade cell wall polysaccharides and obtain free sugars for fermentation and ethanol production. Biorefinary is equally important as more efficient processes have (and can) been developed. Furthermore, green chemistry is being studied as biomass used for bioenergy can also serve as a source of many valuable compounds to be used as pharmaceuticals, cosmetics and other biotechnological products. As all this has to be done with minimal impacts on the environment, research is also focused on improving environmental sustainability, with intense scientific activity to understand carbon emissions and the impacts on water and land used provoked by Biofuels production. Although ethanol has been the primary strategic target, new sources of biodiesel from seeds and algae are starting to be studied, mainly by prospecting new species and understanding chemical composition. The actual state of the Brazilian S&T system is that the country is seriously investing in coordinated actions that we expect to lead to a highly efficient science based production of energy from biomass, having social inclusion and the lowest possible environmental impact.
12. Cultivating Sugarcane in Brazil
Heitor Cantarella
Sugarcane is a tropical grass grown in more than 100 countries mostly between the parallels 35°N and 35°S, covering an area of about 22 million hectares, which represents 0.45% of the world’s agricultural area or 1.6% of the arable area. Yield of cane is approximately 1.6 billion t. Brazil is the largest producer and accounts for 33% of the world production. Optimum temperature for cultivation is between 30 and 34°C and plant growth is greatly reduced below 21°C for most varieties. However, in the maturation stage, sucrose accumulation is triggered by dry conditions or low temperature, usually with average temperatures below 20°C. Sugarcane belongs to the Saccharum genus and comprises several species although plants presently cultivated are mostly hybrids derived from S. officinarum, S. spontaneum, S. robustum, S. sinnensis, and S. barberi.. Sugarcane in one of the most efficient plants to convert solar energy into biomass. The Brazilian average stalk yield is around 85 t ha-1 but varies with soil, climate, cycle length, and growing conditions. Under favorable conditions yield may reach more than 200 t ha-1 but the theoretical yield may be as high as 350 or 400 t ha-1. The stalks of most commercial varieties contain 10 to 16% fibers and 84 to 90% juice. The latter contains 75 to 82% water and 18 to 25% soluble solids of which the great part (15 to 24% of the sugarcane juice) is sucrose and 1 to 2.5% are non-sugars such as amino acids, fatty acids, waxes and mineral components. Therefore, one ton of sugarcane yields about 130 to 170 kg of sucrose and 82 L of ethanol. Other uses for the sugarcane plant include liquors and spirits for human consumption, feedstock for chemical industry, fodder for animals etc. Sugarcane is planted with cuttings (seed cane) instead of seeds. Usually 8 to 12 ton of 8 to 10-month old stalks containing 12 to 18 buds per meter are planted in furrows spaced at 0.8 to 2.0 m. The harvest takes place 10 to 24 months after planting. After harvest the plant sends up new stalks or ratoons that will be cut again usually within one year. Normally yields decline in subsequent ratoons but two to ten cuttings can be performed before the crop needs to be planted again, depending on the variety, climate, soil type, and management conditions. Sugarcane is relatively tolerant to soil acidity but limestone application is recommended when soil pH is below 5.5. Fertilizer needs of sugarcane are relatively high. The nutrient content of shoots of a crop yielding 100 t of stalks are around 100 to 154 kg N, 15 to 25 kg P2O5, 77 to 232 kg K2O, and 14 to 49 kg S . Sugar crops account for 7.5 million t of the NPK fertilizers used in 2007-2008, representing 4.5% of the world fertilizer consumption. In Brazil 23% of the N, 8.7% of the P and 21% of the K fertilizer are used in sugarcane. Nitrogen and potassium are the nutrients used in largest amounts. Sugarmills export mainly sugar and ethanol, which contain only C, H, and O. Therefore, most of the mineral components of the plant may be recycled back to the fields as vinasse, filter cakes, ashes, and other residues, thus reducing the needs of fertilizer and improving the environmental budget of this crop. Biological control, resistant varieties, and management practices are employed to control a number of pests and diseases so that the use agrochemicals in sugarcane is small compared to most field crops.
13. Co-Products from Biomass to Increase Yield and Improve Environmental Impacts
Kenneth F. Reardon
To date, research, development, and commercialization within the bioenergy industry has focused on the production of biofuels, with any unconverted biomass used for production of electricity, biogas, animal feed, or fertilizer. However, both the economics and the environmental impacts of biofuel production could be improved by developing processes to obtain a wider range of chemicals (with higher value) from biomass. Example products range from commodity chemicals such as dicarboxylic acids to nutraceuticals. This presentation will outline options, including extraction and conversion, for producing these non-fuel chemicals from plants and algae. Such processes would lead to a more diverse and sustainable biorefinery.
14. Tailoring biomass to fit the biofuels pipeline.
Maureen C. McCann
Second-generation biofuels will be derived from lignocellulosic biomass using biological catalysts to convert the carbon in plant cell wall polysaccharides to ethanol or other biofuels. The Center for Direct Catalytic Conversion of Biomass to Biofuels (C3Bio) is a DOE-funded Energy Frontier Research Center, which aims to develop transformational technologies to maximize the energy and carbon efficiencies of biofuels production. Heterogeneous chemical catalysis using inorganic and robust catalysts provides an alternative strategy to biological fermentation routes for the production of advanced biofuels, including alkanes and the aromatic components characteristic of gasoline. Designing new catalysts for converting lignocellulosic biomass to biofuels requires understanding the interactions of catalysts with the chemical and physical structures of the biomass at scales ranging from atoms to macromolecules. We are also exploring thermal treatments, including fast-hydropyrolysis, that may generate a bio-crude oil suitable for catalytic upgrading. Our preliminary data show that the composition of maize stover impacts the spectrum of fragments derived from pyrolysis molecular-beam mass spectrometry (PyMBMS). This method relies on thermal degradation of the cell wall constituents under anoxic conditions to provide information about hexose and pentose content, and the content and composition of phenolic compounds derived from lignin and hydroxycinnamic acids. The fact that we can detect changes in spectral profiles from PyMBMS of different genetic lines of maize indicates that specific alterations in the carbohydrate-lignin architecture of the cell wall may improve the selectivity of reaction products and the efficiency of fast-hydropyrolytic and catalytic conversion. We are generating variants of cell wall structures, by manipulation of endogeneous plant genes, and transgenic lines that incorporate catalysts directly or functionalized sites for future catalysis as the plants grow, that is, biomass tailored for its end-use in new conversion processes.
15. Assemble the sugarcane genome, the use R570 BACs as a start.
Marie Anne Van Sluys
Sugarcane, a non-cereal grass, probably has one of the most complex crop genome studied to date, mainly due to its polyploidy and inter-specific origin. Modern cultivars are hybrid organisms distant only a few meiosis from the original cross due mostly to its clonal propagation. Genome size is estimated to 10Gb and monoploid genome at about 1 Gb similar to other Poaceae basic genome compplement. The aim of this work is to evaluate the sugar cane genome sequence using a BACs sequencing strategy and further in silico comparisons to the available Sorghum and Oryza genomes. Transposable elements are mobile genetic sequences which play important roles as donors of functional proteins domains, usable for the formation of new genes, and as promoters of genetic variability in all living organisms. LTR retrotransposons constitute a major fraction of the genomes of higher plants. Since LTR retrotransposons are believed to have contributed significantly to the evolution of genome structure and function, they are an important feature to better understand sugarcane genomic evolution. Here we report the analysis of 30 BAC sequences from sugarcane R570. Assembly using 454 and Sanger are evaluated and gene content in the vicinity of TE is depicted. Reference full-length sequence for several TEs was determined, both from transposons and retrotransposons. Results provide the initial steps towards the assembly of the sugarcane genome and join other efforts to understand the structure and diversification of this important sweet crop.
Supported by BIOEN-FAPESP. 1690756
16. Variation of lignin content, composition and spatial distribution in Saccharum spp. and the effects in ethanol second generation production from bagasse.
Marcelo E. Loureiro
Between cultivated hybrids, low variation in lignin content was found, but differences in syringil/guaicyl ratios could reach 30% variation. Comparing different Sacharum species, the highest levels of lignin was found in S spontaneum, with intermediate levels for S. barberi, S. officinarum and hybrids between each other. Spatial localization of lignin differ sharply spatially and during development: whereas in S. spontaneum culm parenquima cells had already strong lignin deposition in all cell of stalk parenchyma beginning in the second internode, and increasing progressively, modern cultivated hybrids, have only lignin deposition in vascular bundles, and late, in internode 9, some additional deposition restricted only to vascular neighbors cells. Results for differences in sacharification, shows that differences in lignin content from to around 22 to 24% do not have effects in sacharification efficiency, but changes in S/G ratios and ferulic acid contents have significant effects in sacharification. This results suggest that introgression of genes for increase in biomass production from S. spontaneum could have negative effects in the yield of ethanol production from bagasse and special phenotyping will be need to advance breeding to high biomass with higher ethanol production, and composition of lignin and cell wall phenolics seems to be an important target to explore in order to increase the efficiency of this process.
17. Capturing the diversity of maize for the improvement of energy grasses
Nicholas Carpita
Grass species represent a major feedstocks for biofuel production. Most of the biomass is contributed by cell walls that are distinct in composition from all other flowering plants. Identifying cell wall-related genes and their functions underpins a fundamental understanding of growth and development in these species. Toward this goal, we are building a knowledge base of the maize genes involved in cell wall biology, their expression profiles, and the phenotypic consequences of mutation for translational genomic studies in potential energy grasses. Over 750 maize genes were annotated and assembled into gene families predicted to function in cell wall biogenesis. Comparative genomics of maize, rice, and Arabidopsis sequences reveal differences in gene family structure between grass species and a reference eudicot species. These differences in gene family structure and expression between Arabidopsis and the grasses underscore the requirement for a grass-specific genetic model for functional analyses. Application of next generation massively parallel short-read sequencing protocols enhance sensitivity at least 100-fold over long read protocols. I will report expression profiles of cell wall-related genes during several developmental stages in the formation of the sclerenchyma of the maize stem. Future studies will test mutants and transgenic lines of maize for release of glucose and xylose in functional analyses of genes that impact structure and degradability of non-cellulosic polysaccharides. Our research with tropical cultivars of maize and with sweet sorghum demonstrate distinct advantages of these annual crops over perennial grasses.
18. Modification of plant cell wall sugar composition for biorefining and bioenergy.
Paul Dupree
Plant cell wall polysaccharides are of enormous importance in industry and agriculture. There are many issues with the use of biomass for renewable products, including the difficulty in extracting the polymers and converting to monosaccharides. We do not fully understand either the role of the different plant cell wall components or how they might best be altered to improve their properties for the various applications. In the BBSRC sustainable bioenergy centre we are discovering the processes of cell wall synthesis, and studying the importance for plant growth and for processing. Most plant cell wall polysaccharides are synthesized in the Golgi apparatus by a largely unknown set of enzymes. To discover proteins involved in the synthesis of these glycans, we have been analyzing the protein composition of the Golgi apparatus by developing new proteomics tools. We have identified putative glycosyltransferases, sugar transporters and other novel proteins in the Golgi apparatus in Arabidopsis. We prioritise the study of candidates by integrating transcriptomic and proteomic datasets to predict function. We are studying the corresponding mutant plants using our enzymatic polysaccharide profiling technique PACE, which reveals structure and quantity of oligosaccharides released by cell wall polysaccharide digestion. Plants with altered xylan and glucomannan cell wall polysaccharides have recently been identified, and can begin to suggest the potential for future breeding plants with altered biomass composition.
19. Sugarcane Physiology for Bioenergy Production in the Tropics
Paul H. Moore
Sugarcane, Saccharum spp. hybrids, is an important food and bioenergy source and a significant component of the economy in many countries in the tropics and subtropics. Sugarcane and its progenitor species in the genus Saccharum of the subtribe Saccharinae are among the world’s most efficient crops in converting solar energy into chemical energy. The very high levels of biomass production and the efficiency with which ethanol can be produced from its extracted juice have made sugarcane a leading candidate crop for bioenergy production in the tropics. Although we have a century long history of increasing cane and sugar yields through improvements made in sugarcane varieties and agronomic practices, recent gains have been slower. This slow down in yield gains indicates a possible yield ceiling and the need to explore alternative approaches for continued improvement in bioenergy production. Actual and theoretical yields of sugarcane will be analyzed to suggest physiological areas and approaches that might be altered to increase its value as a bioenergy crop.
20. Mitigating environmental impacts of bioenergy production
Plínio B. de Camargo
A certain system for production, consumption, or disposal of goods or services, that can characterize impacts due the cumulative effects, promoted by human action to improve the living conditions of man, can often, in a more profound analysis, put in danger the space around him, whether in the present or in the future. The Life Cycle Analysis (LCA) methodology seeks to assess and quantify the use of natural resources and pollution emissions. It also accounts the main material and energy flows that participate in the generation of a product or process. As such it is possible to assess the potential impacts on the environment coming from the whole production chain, from cradle to grave of a product and its by-products. Taking a look at the bioethanol, when filling a vehicle with sugarcane ethanol, the environmental impacts regarding its use are related with energy balance (relation between the renewable energy generated and fossil energy consumed), balance of GHG emissions, water usage, lost of biodiversity, discharge of vinasse, high production of bagasse, and others environmental impacts also included in the (LCA), such as acidification of soil, water and air, ozone photochemistry formation, nitrification, eutrophication of the water and general human toxicity. Most of these impacts have been studied isolated in the last years and needed to be integrated. Ethanol from sugar cane has several advantages over other types of biofuels, both in terms of a more efficient energy balance as well as a lower water footprint to produce the feedstock, and a industrial water use similar to those consumed to process crude oil. However, the vigorous increase in sugar cane area occurred in the last years and what we wait for the future, suggests that studies in LCA are especially important.
21. Microalgal Biofuels: a Systems Approach
Richard Sayre
One of the more environmentally sustainable ways to produce energy and capture carbon dioxide is the conversion of solar energy into biomass. The first-generation biofuels (alcohol and diesel) were produced from only a few crop systems including, sugar cane (sugar), maize (starch), and soy (oil). These biofuel systems were often not very efficient. Typically, only a fraction of the solar energy captured in biomass was harvested as fuel. Inefficiencies in feedstock processing further reduced the recoverable energy and reduced net carbon capture. Extensive land area was also required to produce fuels from first-generation biofuel crops. Second-generation biofuel systems utilizing cellulose and hemicellulosics are now being developed. Conversion of cellulosics to sugars using advanced enzyme catalysts promises to increase the available carbon resources for fuel production and reduce the land area required for biofuel production. Second generation biofuel systems, e.g., miscanthus and switch grass, can reduce competition with food production, require less agronomic (fertilizer, plowing, pesticide) inputs, and have lower environmental impact than first-generation biofuels. Third generation biofuel systems will offer additional advantages of improved productivity, less impact on agriculture and greater carbon capture. Algae have the greatest biomass yield potential and are capable of producing 2-10 times more fuel per acre than any terrestrial crop system with reduced environmental impact. We are using advanced molecular and engineering strategies to enhance biofuel production and harvesting from algae including enhanced photosynthetic efficiencies and conversion of sugars into oils. We also have developed non-destructive processes for continuous oil extraction from live algae that do not require concentrating algae before extraction. This system substantially reduces residence time in ponds and increases oil productivity. These and other developments in the sustainable production of biofuels from algae will be discussed.
22. Nutrient and Water Cycles in the Bioeconomy: A Life Cycle Perspective
Robert Anex
Examinations of the life cycle environmental performance of biofuels often reveal significant impacts associated with alterations of nutrient cycles. Impacts include eutrophication, acidification, and GHG emissions. The use of synthetic fertilizers in agriculture has significantly altered natural nutrient cycles, greatly increasing both concentration and total quantity of nutrients in the environment. Less well understood but also potentially significant are the impacts of biofuels on the hydrologic cycle. Land use and cropping system choices significantly alter both the quantity and quality of water moving through the environment. Emerging markets for fuels and chemicals from crop biomass are creating new opportunities for redesigning agricultural systems for improved ecological function and energy-use efficiency. Innovative bioconversion processes configured to recover key plant nutrients from biomass will allow recycling nutrients to crop fields, thereby closing nutrient cycles and reducing the energetic and economic costs of fertilization. Choices of biofuel feedstock cropping systems and management can improve water quality and reduce environmental impacts associated with the movement of water in the environment. This talk will report recent results of examinations of the cycling of water and plant nutrients in emerging bioenergy systems and the potential to promote development of highly productive agricultural-industrial systems that protect environmental quality.
23. C4 Bioenergy Crops for Cold Climates
Rowan F. Sage
In warm climates, plants utilizing the C4 photosynthetic pathway are recognized as being more productive and resource use efficient than C3 plants of similar growth form and ecological habit; however, in cold climates, C4 plants are generally less productive than C3 species. Consequently, agricultural systems in the vast land mass of Eurasia and North America above 45°N latitude emphasize crops using the C3 pathway. As demonstrated by the perennial C4 grass Miscanthus, C4 photosynthesis is potentially very productive in cooler climates, in large part because it can better exploit the long, warm days of midsummer than C3 species. The key to exploiting higher latitudes is to utilize C4 species and genotypes that are tolerant of both severe winter cold and episodic chilling during the spring growing season. To be successful, a C4 bioenergy crop at high latitude must produce enough leaf area index by late spring to fully exploit the long, warm days of a high latitude summer. It is therefore imperative that candidate C4 grasses are able to expand the leaf canopy during the cooler months of April and May, when chilling events are common and frost may still occur. If cold tolerant lines of candidate C4 species could be identified, then it would facilitate the establishment of a high latitude bioenergy industry in Canada, Russia and the northern USA. In this presentation, recent work examining the freezing and chilling tolerance of five field-grown Miscanthus genotypes will be described. Using electrolyte leakage to assay subzero temperature tolerance of overwintering Miscanthus rhizomes, we observed little genotypic variation. All genotypes showed 30% to 50% electrolyte leakage at -10°C. Electrolyte leakage of 30% to 50% proved lethal in all cases examined. At the field site where the rhizomes were harvested, air temperatures declined to below -20°C, but soil temperatures remained above -5°C, such that rhizomes remained viable in winter. Little ability to acclimate to colder exposure temperatures was observed over the course of the winter; however, buffering by ground insulation from extreme air temperatures may have prevented the need for acclimation to more intense cold than 0° to -5°C. To assess cold acclimation potential, experiments specifically designed to induce cold hardening below -5°C will need to be conducted. Fluorescence screens of Miscanthus and switchgrass genotypes growing in the field showed variable chilling tolerance in May when exposure temperatures fell below 10°C. There does not appear, however, to be any correlation between chilling tolerance as measured by fluorescence, and mid-winter tolerance as measured by electrolyte leakage. These results indicate that Miscanthus could be successfully grown in mid-latitudes where severe winter cold is encountered, so long as rhizomes remain insulated from low air temperature by snow or dirt. To predict where Miscanthus could be grown, we suggest it will be necessary to predict climate zones where soil temperatures are likely to fall below -10°C over the lifespan of a Miscanthus crop.
24. The Potential for Energy Maize as an Improved Annual Biomass Feedstock
Steve Moose
Maize (Zea mays L.) has become the world’s leading grain crop because of its high yields, remarkable genetic diversity, and the ease by which this diversity has allowed the adaptation of this once tropical grass to a wide variety of cropping systems. A key physiological trait influencing maize yields is shoot maturation, the progression from seedling to vegetative and then reproductive growth. Shoot maturation is highly-responsive to photoperiod, and reductions in photoperiod sensitivity have contributed significantly to higher grain yields in temperate environments. However, recent interest in developing renewable energy from agricultural feedstocks has again highlighted the potential of alternative maize ideotypes that maximize total biomass yields and conversion efficiencies while reducing greenhouse gas emissions. Field trials conducted in Illinois during the past five years have demonstrated that maize hybrids derived from crossing tropical- and temperate-adapted parents can produce higher total biomass yields and accumulate greater amounts of stalk sugars compared to commercial corn grain hybrids, particularly when grown with low nitrogen inputs. These “energy maize” maize hybrids combine the enhanced vegetative growth resulting from photoperiod sensitivity with superior agronomic traits selected during the past century of breeding for high grain yields. In addition to tropical-by-temperate crosses, we have also demonstrated that increasing the expression of the Glossy15 gene, a key regulator of shoot maturation in maize, also enhances biomass yields, stalk sugars, and N utilization. Collectively, these findings suggest a number of paths forward for optimizing maize hybrids for the emerging bioenergy industry.
25. Miscanthus – A cool bioenergy cane?
Stephen Long
Miscanthus giganteus is closely related to sugarcane, yet is one of the most cold-tolerant C4 species known. It can yield up to 30 dry tonnes per hectare (t/ha) at 52 N in Britain and up to 60 t/ha in the US Midwest. Its ability to recycle and fix nitrogen, its large perennial root/rhizome system, and its high water use efficiency make it particularly sustainable. It will be shown that it outyields switchgrass via much higher photosynthetic rates and outyields maize through its ability to produce and maintain functioning leaves at lower temperatures, so achieving a much longer growing season. Key to its success is its ability to maintain high photosynthetic rates during chilling conditions (< 14C). This is shown to correspond to over-expression of the gene for pyruvate-Pi-dikinase (PPDK) and the chloroplastic protein that it codes, in contrast to other C4 species. Changes in transcript profiles associated with chilling acclimation will be presented.
26. Struture, biosynthesis and evolution of xylans in Embryophytes
William York
Xylans are the most abundant hemicellulosic component of the secondary cell walls of many plant species. Xylans have important functions in plant development and physiology, contributing to the biogenesis of vascular tissues and affecting the recalcitrance of woody tissues to biological saccharification. Although certain phylogenetic groups of plants have evolved to produce xylans with structural diversity, xylans with remarkably similar features have been found in a wide range of species. The structural characterization and localization of xylans in diverse species of embryophytes, in combination with phylogenetic and biochemical analyses, provide information required to test hypotheses regarding the appearance and evolution of xylans and the biosynthetic mechanisms leading to xylan production. Mechanistic models for xylan biosynthesis will be described and evaluated in light of recent data generated in our laboratory and elswhere.
27. Identification of secreted proteins from Brachypodium distachyon
Rafael Pont Lezica
Plant biomass (or ‘lignocellulose’) is one of the greatest untapped reserves on the planet and is mostly composed of cell walls. Energy-rich polysaccharide polymers make up about 75% of plant cell walls and, in theory, these can be broken down to produce sugar substrates (saccharification) from which a whole range of useful products can be made (e.g. bioplastics, fine and bulk chemicals, food and feed ingredients), including bioethanol (i.e. the biorefinery concept). However, the complex structure of cell walls, consisting of a network of various polysaccharides, and glycoproteins encrusted by phenolic polymers, or lignin, makes them very resistant to degradation. Improving the ease and yield of cell wall saccharification represents the major technological hurdle that must be overcome before the full vision of the plant-fuelled biorefinery can be realized. Brachypodium distachyon (purple false brome) has many qualities that make it a model for functional genomics studies in temperate grasses, cereals, and dedicated biofuel crops such as Switchgrass or Miscanthus. Its genome was fully sequenced in 2008, allowing the initiation of accurate proteomic studies. In addition to polysaccharides, plant cell walls contain 5-10% of proteins. Recent cell wall proteomic studies have established a range of plant cell wall proteins in Arabidopsis. Currently nearly 500, i.e. approximately one fourth of the predicted, cell wall proteins have been identified. These have subsequently been classified into nine groups, including processive enzymes, expansins, oxido-reductases, proteases, signal transduction components, proteins associated with lipid metabolism, and structural proteins. Only a few cell wall proteomic studies have been performed on monocotyledonous plants, such as maize and rice. Although the obtained proteins from these studies largely lack annotation some of them appeared to be associated with assembly and/or modification of the cell wall polymers, or possibly in cross-linking them. Here we present the first results on Brachypodium secreted proteins from leaves and culms. Important differences were found within organs and young or mature tissues.
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