Cellulosic Biofuel Industry Research Articles

Climate risk management for the U.S. cellulosic biofuels supply chain

As U.S. energy policy turns to bioenergy, and second-generation biofuels in particular, to foster energy security and environmental benefits, consideration should be given to the implications of climate risk for the incipient bioenergy industry. As a case-in-point, we review evidence from the 2012 U.S. drought, underscoring the risk of extreme weather events to the agricultural sector in general, and the bioenergy supply chain in particular, including reductions in feedstock production and higher prices for agricultural commodities and biofuels. We also use a risk management framework developed by the Intergovernmental Panel on Climate Change to review current understanding regarding climate-related hazards, exposure, and vulnerability of the bioenergy supply chain with a particular emphasis on the growing importance of lignocellulosic feedstocks to future bioenergy development. A number of climate-related hazards are projected to become more severe in future decades, and future growth of bioenergy feedstocks is likely to occur disproportionately in regions preferentially exposed to such hazards. However, strategies and opportunities are available across the supply chain to enhance coping and adaptive capacity in response to this risk. In particular, the implications of climate change will be influenced by the expansion of cellulosic feedstocks, particularly perennial grasses and woody biomass. In addition, advancements in feedstock development, logistics, and extension provide opportunities to support the sustainable development of a robust U.S. bioenergy industry as part of a holistic energy and environmental policy. However, given the nascent state of the cellulosic biofuels industry, careful attention should be given to managing climate risk over both short- and long-time scales.

Effect of salts on the Co-fermentation of glucose and xylose by a genetically engineered strain of Saccharomyces cerevisiae

BackgroundA challenge currently facing the cellulosic biofuel industry is the efficient fermentation of both C5 and C6 sugars in the presence of inhibitors. To overcome this challenge, microorganisms that are capable of mixed-sugar fermentation need to be further developed for increased inhibitor tolerance. However, this requires an understanding of the physiological impact of inhibitors on the microorganism. This paper investigates the effect of salts on Saccharomyces cerevisiae 424A(LNH-ST), a yeast strain capable of effectively co-fermenting glucose and xylose.ResultsIn this study, we show that salts can be significant inhibitors of S. cerevisiae. All 6 pairs of anions (chloride and sulfate) and cations (sodium, potassium, and ammonium) tested resulted in reduced cell growth rate, glucose consumption rate, and ethanol production rate. In addition, the data showed that the xylose consumption is more strongly affected by salts than glucose consumption at all concentrations. At a NaCl concentration of 0.5M, the xylose consumption rate was reduced by 64.5% compared to the control. A metabolomics study found a shift in metabolism to increased glycerol production during xylose fermentation when salt was present, which was confirmed by an increase in extracellular glycerol titers by 4 fold. There were significant differences between the different cations. The salts with potassium cations were the least inhibitory. Surprisingly, although salts of sulfate produced twice the concentration of cations as compared to salts of chloride, the degree of inhibition was the same with one exception. Potassium salts of sulfate were less inhibitory than potassium paired with chloride, suggesting that chloride is more inhibitory than sulfate.ConclusionsWhen developing microorganisms and processes for cellulosic ethanol production, it is important to consider salt concentrations as it has a significant negative impact on yeast performance, especially with regards to xylose fermentation.

The potential of C4 grasses for cellulosic biofuel production.

With the advent of biorefinery technologies enabling plant biomass to be processed into biofuel, many researchers set out to study and improve candidate biomass crops. Many of these candidates are C4 grasses, characterized by a high productivity and resource use efficiency. In this review the potential of five C4 grasses as lignocellulosic feedstock for biofuel production is discussed. These include three important field crops—maize, sugarcane and sorghum—and two undomesticated perennial energy grasses—miscanthus and switchgrass. Although all these grasses are high yielding, they produce different products. While miscanthus and switchgrass are exploited exclusively for lignocellulosic biomass, maize, sorghum, and sugarcane are dual-purpose crops. It is unlikely that all the prerequisites for the sustainable and economic production of biomass for a global cellulosic biofuel industry will be fulfilled by a single crop. High and stable yields of lignocellulose are required in diverse environments worldwide, to sustain a year-round production of biofuel. A high resource use efficiency is indispensable to allow cultivation with minimal inputs of nutrients and water and the exploitation of marginal soils for biomass production. Finally, the lignocellulose composition of the feedstock should be optimized to allow its efficient conversion into biofuel and other by-products. Breeding for these objectives should encompass diverse crops, to meet the demands of local biorefineries and provide adaptability to different environments. Collectively, these C4 grasses are likely to play a central role in the supply of lignocellulose for the cellulosic ethanol industry. Moreover, as these species are evolutionary closely related, advances in each of these crops will expedite improvements in the other crops. This review aims to provide an overview of their potential, prospects and research needs as lignocellulose feedstocks for the commercial production of biofuel.

Cloning and identification of novel hydrolase genes from a dairy cow rumen metagenomic library and characterization of a cellulase gene.

BackgroundInterest in cellulose degrading enzymes has increased in recent years due to the expansion of the cellulosic biofuel industry. The rumen is a highly adapted environment for the degradation of cellulose and a promising source of enzymes for industrial use. To identify cellulase enzymes that may be of such use we have undertaken a functional metagenomic screen to identify cellulase enzymes from the bacterial community in the rumen of a grass-hay fed dairy cow.ResultsTwenty five clones specifying cellulose activity were identified. Subcloning and sequence analysis of a subset of these hydrolase-positive clones identified 10 endoglucanase genes. Preliminary characterization of the encoded cellulases was carried out using crude extracts of each of the subclones. Zymogram analysis using carboxymethylcellulose as a substrate showed a single positive band for each subclone, confirming that only one functional cellulase gene was present in each. One cellulase gene, designated Cel14b22, was expressed at a high level in Escherichia coli and purified for further characterization. The purified recombinant enzyme showed optimal activity at pH 6.0 and 50°C. It was stable over a broad pH range, from pH 4.0 to 10.0. The activity was significantly enhanced by Mn2+ and dramatically reduced by Fe3+ or Cu2+. The enzyme hydrolyzed a wide range of beta-1,3-, and beta-1,4-linked polysaccharides, with varying activities. Activities toward microcrystalline cellulose and filter paper were relatively high, while the highest activity was toward Oat Gum.ConclusionThe present study shows that a functional metagenomic approach can be used to isolate previously uncharacterized cellulases from the rumen environment.

Transportation Infrastructure Implications of Development of a Cellulosic Biofuels Industry for Indiana

Development of a cellulosic biofuels industry in biomass-rich states such as Indiana would cause substantial impacts on road infrastructure. This research estimated the infrastructure impacts of cellulosic biofuel production using three Indiana cellulosic facility sites. Following are key results: Average loaded vehicle trip miles (VTM) are projected to be 101 to 583% higher per gallon of cellulosic biofuel capacity compared to the VTM per gallon of capacity for grain-based ethanol. Average ton-miles per gallon of capacity for cellulosic biofuel production is projected to be 4 to 255% higher compared to the average ton-mile per gallon of capacity for grain-based ethanol.

Biofuels and agriculture: a past perspective and uncertain future

The US corn ethanol industry has grown from virtually nothing in the early 1980s to over 14 billion gallons in 2011. Subsidies have been an important impetus for the industry, and they have existed in one form or another throughout the life of the industry. This paper provides (1) a brief look at the history of the linkages between energy and agriculture and how they have changed with biofuels; (2) a review of some of the major impacts of the US corn ethanol program; and (3) analysis of prospective impacts of cellulosic biofuels. There is no doubt that biofuels have brought about a new era for global agriculture. Historically, the prices of agricultural and energy products moved in response to supply and demand factors relevant to each market, but moved largely independent of one another. Corn ethanol has changed that, and today there is a link between crude oil and corn that is driven by the demand side. Since agricultural commodity prices are linked both on the demand and supply sides, the corn–crude oil link spills over to other agricultural commodities as well. Development of cellulosic biofuels has been much slower than hoped. The feedstocks are more expensive than initially believed. Conversion technologies remain uncertain and expensive. There are many uncertainties through the cellulosic supply chain, and government policy remains uncertain as well. Thus, the future of the cellulosic biofuels industry is, at this point, an open question.

An assessment of cellulosic ethanol industry sustainability based on industry configurations

Thirty six billion gallons of renewable fuel is US government-mandated by 2022, of which approximately 21 billion gallons will originate from cellulosic sources. This presents a challenge to the cellulosic biofuel industry, although it provides a window of opportunity to bring vision, policy, and science together to guide the industry's sustainable development. The objective of this research was to utilize current scientific knowledge and farmers' prac- tical experience to identify basic characteristics of the cellulosic biofuel industry that will allow it to be most functional and sustainable, such that policy might be developed, if needed, to favorably shape the industry. This study's key participants included 14 scientists actively engaged in biofuel research and 44 farmers or agriculture professionals. The methods used in this study included (1) an integrated open forum and focus group discussions with scientists and (2) a triangulation of a survey and focus group discussion with farmers. Environmental, social, technological, and logistics criteria for four conversion facility configurations were assessed. Scientists assessed multiple-feedstock-species configurations more favorably than single-species configurations for environmental metrics and high/stable feedstock produc- tion. They also assessed distributed units as having fewer logistic challenges than centralized processing units. Distributed multiple-species configurations were also assessed to have greater rural development opportunity than other configurations. In contrast, the centralized single- species configuration was consistently assessed as not different from, or less favorable than, the other three configurations for all of the criteria assessed. Farmers have a significant need and desire for education about the emerging cellulosic biofuel industry but anticipated environ- mental challenges associated with single-species conversion platforms.

The Transportation Emission Impact of the Biomass Feedstock Traffic of A Potential Commercial-Scale Biorefinery in East Tennessee

The logistics required to supply biomass feedstock to a refinery is crucial to the development of the cellulosic biofuel industry because of the importance of the quality and quantity and bulky nature associated with cellulosic feedstock to the biofuel conversion process. In addition, the potential social and environmental impact of biomass feedstock transportation has also received increasing attention due to the expansion of truck traffic on the current road system. This study applies a spatial-oriented mixed-integer mathematical programming model linked to a GIS resource model to generate a least cost solution of a typical feedstock harvest and logistic system for a potential biorefinery with the capacity of 50 million gallons per year. Moreover, U.S. EPA’s MOVES2010a was used to estimate the baseline emissions for 2010 with national scale option in study region and additional emissions generated from hauling those feedstock with project scale option. Results showed that the transportation cost accounted for nearly one-quarter of total plant gate costs of the large round bales. Also, it was estimated that the biorefinery received about 50,000 truckloads per year, hence creating annually 100,000 truck trips (or 274 truck trips per day) on the road linking the entrance of the biorefinery to the supply regions. The overall VMT increase resulting from additional feedstock truck traffics was 3.7 million miles and the emissions of NOX, CO2, PM10, and PM2.5 emissions increased by 0.32%, 0.13%, 0.60%, and 0.71%, respectively, in these 13 counties studied when compared with the overall baseline emissions.

Livestock nutrition – a perspective on future needs in a resource-challenged planet

Global agriculture will be challenged by future population growth in the developing nations in Africa and Asia, concurrent with regional changes in climate that will adversely affect local crop and fodder production. The uncoupling of animal production from land area by global trade in high energy grains and protein meals, which has underpinned industrialised livestock production in the developed world, is forecast to continue in some population growth hotspots of the developing world. However, the projected rise in fossil fuel costs and the greenhouse gas emissions associated with their use will increasingly favour use of non-cereal energy sources, and the extent of feeding cereal grains to livestock in the developing world into the middle of this century is uncertain. Meeting the developing world’s growing demand for meat, milk and eggs in the face of the 3-fold challenge of population growth, climate change and fossil energy decline, demands a fresh vision, and the development of fresh technologies for animal nutrition in coming decades. How can high efficiency production be achieved from feeds of low metabolisability? This question is as critical for aquaculture as it is for land-based production. Enhancing ruminant capacity to generate animal product from crop by-products is fundamental in this achievement, but livestock access to crop residues will be in competition with the emerging second-generation (cellulosic) biofuels industry. Industrial technologies that treat crop residues to improve their nutritive value at source, not just as end-user treatments, will be required. There is scope to boost animal production and also reduce enteric greenhouse gas emissions (e.g. nitrate supplements) and the expanded capability in rumen microbiology may deliver targeted tools to mitigate emissions and increase energy yield from cellulosic feedstuffs. The greatest challenge of tomorrow’s nutritionist, however, is to provide local feed energy resources and enhanced nutrient utilisation, allowing a high yield of animal product without reliance on imported cereal grains and oilseed meals.

Advanced Regional Biomass Processing Depots: a key to the logistical challenges of the cellulosic biofuel industry

AbstractInterest in commercially viable cellulosic biofuel production has greatly increased due to concerns regarding the sustainability of petroleum fuels. While research into solving the technical issues surrounding cellulosic biofuels is ongoing, much less attention has been paid to solving supply chain challenges such as low bulk density of cellulosic biomass, compositional variability and seasonality of the feedstock, food vs fuel issues, and local environmental concerns. To address these supply chain problems, we explore the concept of Regional Biomass Processing Depots (RBPDs), strategically distributed facilities that procure, pre‐process /pre‐treat and densify biomass into stable intermediate products that are compatible with existing bulk commodity logistical systems. In this perspective, we discuss the fundamental concept of RBPDs, their functionality, advantages, and potential challenges. We then extend the analysis of depots to include enhanced configurations and discuss some technologies that might be deployed in RBPD networks and the valuable coproducts that might be produced via synergies among these technologies. © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd

Expression of industrially relevant laccases: prokaryotic style

Laccases are a class of multi-copper oxidases (MCOs) that catalyze the one-electron oxidation of four equivalents of a reducing substrate, with the concomitant four-electron reduction of dioxygen to water. They can catalyze a multitude of reactions, including the degradation of polymers and oxidative coupling of phenolic compounds, positioning them as significant industrial enzymes. Although fungal laccases are well known and well characterized, only recently has in silico biology led to rapid advances in the discovery, characterization and engineered expression of prokaryotic laccases. We describe the recent burgeoning of prokaryotic laccases, their catalytic properties, structural features and molecular evolution, vis-à-vis fungal laccases where possible. Special focus is given to the application of laccases to the emerging cellulosic biofuel industry.

Opportunity for profitable investments in cellulosic biofuels

Research efforts to allow large-scale conversion of cellulose into biofuels are being undertaken in the US and EU. These efforts are designed to increase logistic and conversion efficiencies, enhancing the economic competitiveness of cellulosic biofuels. However, not enough attention has been paid to the future market conditions for cellulosic biofuels, which will determine whether the necessary private investment will be available to allow a cellulosic biofuels industry to emerge. We examine the future market for cellulosic biofuels, differentiating between cellulosic ethanol and ‘drop-in’ cellulosic biofuels that can be transported with petroleum fuels and have equivalent energy values. We show that emergence of a cellulosic ethanol industry is unlikely without costly government subsidies, in part because of strong competition from conventional ethanol and limits on ethanol blending. If production costs of drop-in cellulosic biofuels fall enough to become competitive, then their expansion will not necessarily cause feedstock prices to rise. As long as local supplies of feedstocks that have no or low-valued alternative uses exist, then expansion will not cause prices to rise significantly. If cellulosic feedstocks come from dedicated biomass crops, then the supply curves will have a steeper slope because of competition for land.

The integration of energy and agricultural markets

AbstractThis article addresses the evolving links between energy and agricultural markets. Prior to 2005, there was little correlation between energy and agricultural commodity prices. In 2006–2008, with the ethanol boom in the United States, there emerged a strong link between crude oil, gasoline, and corn prices. There was little link between ethanol and corn. However, in late 2008 and 2009, the markets changed as ethanol production came under severe economic pressure and 2 billion out of 12 billion gallons of capacity shut down. During this period ethanol became priced more on corn, as the breakeven corn price helped drive the ethanol market. This article explores the drivers in these markets as well as other major issues facing the corn ethanol industry in the United States such as the blend wall. The article concludes with a review of prospects of a future cellulosic biofuels industry.

Genetic Analysis of Cell Wall Traits Relevant to Cellulosic Ethanol Production in Maize (Zea mays L.)

Maize hybrids with improved stover yield and quality are needed to support the emerging cellulosic biofuels industry. Knowledge of the genetic variation, covariation, and genetic architecture of agronomic and cell wall traits will help maize breeders improve relevant traits through selective breeding and genetic engineering. We utilized the maize intermated B73 × Mo17 (IBM) recombinant inbred line (RIL) population to map quantitative trait loci (QTL) and to evaluate the genetic relationships among traits relevant for cellulosic biofuel production, including grain yield, stover yield, neutral detergent fiber digestibility (NDFD), and glucan, xylan, and lignin concentration. Intermated B73 × Mo17 RIL were evaluated per se and as testcrosses to W604S to assess how well performance and QTL effects correspond between inbreds and hybrids. There were no unfavorable correlations between agronomic and cell wall traits within the testcross progeny. Polysaccharide content was either positively correlated to, or not correlated to, NDFD, indicating that increasing both carbohydrate content and convertibility is feasible. Quantitative trait loci were identified for all traits evaluated, but few QTL were in common between inbred per se and testcross evaluations despite moderate to high genotypic correlations between progeny types. This study provides information that will support the development of dual‐purpose maize hybrids that are high in grain yield and also high in yield of digestible cellulosic feedstock.

Balancing corn stover harvest for biofuels with soil and water conservation

The emerging cellulosic biofuel industry offers both challenges and opportunities for conserving soil and water resources in an agriculturally productive environment. Crop residues are North America9s most important soil and water conservation resource and concurrently will be the most important feedstock for the emerging cellulosic biofuels industry. This analysis of factors affecting water-induced soil erosion, soil carbon maintenance, and water quality in the emerging cellulosic bioenergy industry identifies a variety of critical issues likely to both directly and indirectly lead to greater degradation of these resources. Pressing issues are also identified for scientific research and for policy analysis. Research should determine more precisely the erosion rates and sediment delivery rates of different biomass cropping systems, determine the acceptable rates of residue removal for different crops and soils in the face of more frequent extreme rainfall events, describe how those removal rates vary spatially across the landscape, develop the harvest technology that removes residue at these rates, and develop a suite of conservation practices appropriate for use with crop residue harvest. Policy analysis should examine land ownership and management patterns to develop a policy environment in which conservation practices are encouraged, or at least not discouraged. A framework must be developed to oversee and insure that residue removal rates are not abusive to soil and water resources.

The DOE BioEnergy Science Center—a U.S. Department of Energy Bioenergy Research Center

The BioEnergy Science Center, a nationally and internationally peer-reviewed center of leading scientific institutions and scientists, is organized and in operation as a U.S. Department of Energy Bioenergy Research Center. This Oak Ridge National Laboratory-led Center has members from top-tier universities, leading national labs, and private companies organized as a single project team, with each member chosen for its significant contributions in the Center’s research focus areas. The recalcitrance of cellulosic biomass is viewed as (1) the most significant obstacle to the establishment of a cellulosic biofuels industry, (2) essential to producing cost-competitive fuels, and (3) widely applicable, since nearly all biofuels and biofeedstocks would benefit from such advances. The mission of the BioEnergy Science Center is to make revolutionary advances in understanding and overcoming the recalcitrance of biomass to conversion into sugars, making it feasible to displace petroleum with ethanol and other fuels.

Expediting the biofuels agenda via genetic manipulations of cellulosic bioenergy crops

AbstractCellulosic bioenergy crops are crops whose cellulosic matter could be converted into biofuels. The petroleum industry makes its profit not only from petro fuels, but also from petroleum‐derivative coproducts, such as lubricants and aromatic petrochemicals, that are used for production of other hydrocarbon compounds. This review explains how using the petroleum industry model in cellulosic biofuels industry could sharply increase profi tability via production of high‐value, low‐volume recombinant coproducts, such as biopharmaceuticals, and high‐value industrial chemicals in cellulosic bioenergy crops. The two major expenses associated with the production of cellulosic biofuels include the costs of pre‐treatment processes and the costs of microbial cellulases. This review summarizes the role of biomass crop genetic manipulations to reduce these costs. It also describes the challenges that farmers will soon face because of the monoculture of new bioenergy crops, such as perennial grasses, and how genetic manipulations of these crops could overcome such challenges. Finally, this review addresses concerns about the effect of cellulosic biomass removal from soil on the soil carbon reserve and the role that crop transgenic technology will play to assure sufficient carbon sequestration in soil. It also addresses the role that modern crop genetic engineering technology plays in avoiding the presence of herterologous coproducts in the food chain to overcome consumer concerns. © 2009 Society of Chemical Industry and John Wiley & Sons, Ltd

Crop, Native Vegetation, and Biofuels: Response of White‐Tailed Deer to Changing Management Priorities

ABSTRACT The expansion of the cellulosic biofuels industry throughout the United States has broad‐scale implications for wildlife management on public and private lands. Knowledge is limited on the effects of reverting agriculture to native grass, and vice versa, on size of home range and habitat use of white‐tailed deer (Odocoileus virginianus). We followed 68 radiocollared female deer from 1991 through 2004 that were residents of DeSoto National Wildlife Refuge (DNWR) in eastern Nebraska, USA. The refuge was undergoing conversion of vegetation out of row‐crop agriculture and into native grass, forest, and emergent aquatic vegetation. Habitat in DNWR consisted of 30% crop in 1991 but removing crops to establish native grass and wetland habitat at DNWR resulted in a 44% reduction in crops by 2004. A decrease in the amount of crops on DNWR contributed to a decline in mean size of annual home range from 400 ha in 1991 to 200 ha in 2005 but percentage of crops in home ranges increased from 21% to 29%. Mean overlap for individuals was 77% between consecutive annual home ranges across 8 years, regardless of crop availability. Conversion of crop to native habitat will not likely result in home range abandonment but may impact disease transmission by increasing rates of contact between deer social groups that occupy adjacent areas. Future research on condition indices or changes in population parameters (e.g., recruitment) could be incorporated into the study design to assess impacts of habitat conversion for biofuel production.

Biofuels: a major rural economic development opportunity

AbstractThis perspective addresses the rural development implications of developing a cellulosic biofuels industry to meet current mandates. While biofuels development has been generally assumed to be positive for rural economies, the potential economic contribution of biofuels has not been quantifi ed. We compare the economic contribution (economic impact) of a biomass‐based ethanol plant with that of a corn‐based facility. The cellulosic biorefi nery has a much greater contribution because the feedstock payments represent new income for farmers and those involved in the supply process, whereas corn has alternative markets. We then explore the implications of developing a cellulosic‐based industry at a scale to meet the 16‐billion‐gallon cellulosic biofuel mandate of the Energy Independence and Security Act of 2007. The economic effects for rural areas with high feedstock potential could be substantial. © 2008 Society of Chemical Industry and John Wiley & Sons, Ltd

The Billion-Ton Biofuels Vision

![Figure][1] In 1895, Swedish chemist Svante Arrhenius presented a paper to the stockholm Physical Society titled On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground , in which he argued that the combustion of fossil fuel would lead to global warming. He was right, so we must deal with the consequences of global climate change and somehow meet our expanding energy needs while limiting greenhouse gas emissions. Earth receives approximately 4000 times more energy from the Sun each year than humans are projected to use in 2050. Some of that energy can be captured through a variety of “renewable” sources, but the only form of solar energy harvesting that can contribute substantially to transportation fuel needs at costs competitive with fossil fuel is that captured by photosynthesis and stored in biomass. Brazil now obtains a quarter of its ground transportation fuel from ethanol produced by the fermentation of sugarcane sugar, and in the United States, approximately 90 corn grain-to-ethanol refineries produce about 4.5 billion gallons of ethanol annually. The U.S. Energy Policy Act of 2005 would increase that production to 7.5 billion gallons by 2012, but the United States currently uses about 140 billion gallons of ground transportation fuel per year. To replace 30% of that amount with ethanol of equivalent energy content, as proposed recently by the Secretary of Energy, will require about 60 billion gallons of ethanol. A recent analysis[*][2] concluded that the United States could produce about 1.3 billion dry tons of biomass each year in addition to present agricultural and forestry production. Because it is theoretically possible to obtain about 100 gallons of ethanol from a ton of cellulosic biomass (such as corn stover, the stalks remaining after corn has been harvested), the United States could sustainably produce about 130 billion gallons of fuel ethanol from biomass. In addition to a positive effect on the release of greenhouse gases, a biofuels program on this scale would have substantial economic and strategic advantages. ![Figure][1] CREDIT: ROYALTY-FREE/CORBIS The creation of a new industry on that scale will require much basic and applied work on methods for converting plant lignocellulose to fuels, because several significant problems must be overcome to make the process ready for large-scale use. For example, cellulose is a recalcitrant substrate for bioconversion, and unacceptably large amounts of enzymes are required to produce sugar. Lignin occludes polysaccharides and inhibits enzymatic hydrolysis of these carbohydrates; energetically expensive and corrosive chemical pretreatments are required for its removal. The yeast currently used in large-scale ethanol production cannot efficiently ferment sugars other than glucose. And relatively low concentrations of ethanol kill microorganisms, requiring an expensive separation of the product from large volumes of yeast growth medium. These and other technical issues associated with this emerging industry have potential solutions, and many incremental advances can be envisioned. However, substantial public and private investment will be needed to meet the nation's goals. For instance, competitive funding for basic research in plant biology by all federal agencies totals only about 1% of the National Institutes of Health's budget. Small wonder that we do not know basic things such as the composition of the enzyme complex that synthesizes cellulose. Hopefully, a new U.S. Department of Energy (DOE) report[†][3] that outlines the scientific issues will help set the direction for increased funding in this area. A national biofuels strategy will ultimately depend on massive support for basic curiosity-driven research in many aspects of nonmedical microbiology, plant biology, and chemical engineering. A fivefold increase in federal support during the next decade could readily be justified by the projected economic gains from the accelerated development of a cellulosic biofuel industry. To ensure parallel progress on the many different components of a biofuels strategy, it may be necessary to create a mission-oriented project similar to the Manhattan Project. Indeed, several of the national laboratories that were founded during the Manhattan era also pioneered some aspects of biofuel technology and could be a powerful source of relevant scientific and engineering expertise. [1]: pending:yes [2]: #fn-1 [3]: #fn-2