What is cellulosic ethanol made from?
The United States Department of Energy (DOE) provides a one-page primer on cellulosic feedstocks, including their main components, primary sources, and advantages. The site also contains a link to their “ABCs of Biofuels.”
How is cellulosic ethanol made?
The following link provides an easy-to-understand overview of cellulosic ethanol that Mascoma co-founder Charles Wyman wrote for the Materials Research Society in 2008. In addition to describing the biological conversion process, the article also considers the benefits of cellulosic ethanol, technical and economic progress made to date, and the commercial challenges faced by the nascent industry.
The Energy Crisis
The following link—developed as part of an environmental studies course at Middlebury College—presents an overview of the 1970s energy crisis, including a brief historical backdrop, facts and statistics from the embargo years, causes and effects, responding governmental policies, and the look toward alternative energy.
History of Fuel Ethanol
This paper assesses the progress and evolution of the ethanol industry from one based on corn and sugarcane to one expected to be based on cellulosic biomass. The authors trace the development of fuel ethanol from the early stages of the automobile industry to its use today as a substitute liquid fuel. Consideration of production economics and enabling public polices is also provided.
Solomon BD, Barnes JR, Halvorsen KE, 2007. Grain and cellulosic ethanol: History, economics, and energy policy. Biomass and Bioenergy 31:416-425.
The fuel of the future, according to both Henry Ford and Charles F. Kettering—the first head of research at General Motors—was ethanol made from farm products and cellulosic materials. This paper considers the history of fuel ethanol, including the competition between lamp fuels in the 19th century; the scientific studies about alcohol as a fuel in the early 20th century; the development of "ethyl" leaded gasoline as a bridge to the "fuel of the future" in the 1920s; the worldwide use of alcohol—gasoline blends in the 1920s and 30s; and the eventual emergence of the farm "Chemurgy" movement and its support for alcohol fuel in the 1930s.
This site presents the history of cellulosic ethanol, from the first attempt at commercialization in Germany in 1898 with a process involving acid hydrolysis of wood to today’s current efforts.
Production potential of cellulosic ethanol:
This landmark article in the Journal Science written by co-founders Lee Lynd and Charles Wyman—their first collaboration—examines the large-scale potential of cellulosic ethanol, including consideration of energy balance, feedstock supply, environmental impact, energy security, and economics.
Lynd, L.R., J.H. Cushman, R.J. Nichols, C.E. Wyman. 1991. Fuel ethanol from cellulosic biomass. Science. 251:1318-1323.
Overview of cellulosic ethanol:
Mascoma co-founder Lee Lynd—in this comprehensive Annual Review of Energy and the Environment paper—covers all the bases of cellulosic ethanol including: fuel performance, feedstocks, conversion technology, process economics, environmental impact, research priorities, and commercialization.
Lynd, L.R. 1996. Overview and evaluation of fuel ethanol from cellulosic biomass: Technology, economics, the environment, and policy. Ann. Rev. Energy Environ. 21:403-465.
What is Consolidated Bioprocessing (CPB)?
This paper describes the concept of consolidated bioprocessing and R&D efforts to make CBP a commercial reality.
Lynd, L.R., W.H. van Zyl, J.E. McBride, M. Laser. 2005. Consolidated bioprocessing of cellulosic biomass: an update. Curr. Opin. Biotechnol. 16:577-583.
Review of consolidated bioprocessing (CBP)
The first—and still definitive—scholarly treatment of microbial cellulose utilization and consolidated bioprocessing, including fundamental concepts, analytical methods, quantitative consideration of cellulose hydrolysis, biological processing, and organism development.
Lynd, L.R., P.J. Weimer, W.H. van Zyl, I.S. Pretorius. 2002. Microbial cellulose utilization: fundamentals and biotechnology. Microbiol. Mol. Biol. Rev. 66:506-577.
The Global Outlook for Industrialization of Biofuels
This article summarizes the proceedings and discussions from a 2009 conference “The Biofuel Situation and Policies in Developing Countries”, including the potential, necessary investments and institutional changes by the private sector, and important government investments and policies.
This article from the United States Department of Agriculture’s Economic Research Service considers the interrelated factors affecting the global expansion and growth of biofuels, including the future price of oil, availability of low-cost feedstocks, sustained commitment to supportive governmental policies, technological breakthroughs, and competition from unconventional fossil fuel alternatives.
This web site explores the potential of plastics made from plants such as corn, potatoes, sugarcane, and trees.
Conservation is paramount
This landmark paper introduced the concept of climate change mitigation “wedges” and made it clear that addressing the problem requires a portfolio of actions—with conservation being prominent—rather than a single “silver bullet”.
Pacala S, Socolow R, 2004. Stabilization Wedges: Solving the Climate Problem for the Next 50 Years with Current Technologies. Science 305:968-972.
This site summarizes expert discussion regarding the role of conservation that stemmed from a day-long March 2009 forum sponsored by the American Association for the Advancement of Science. The emerging consensus opinion: policymakers worldwide should make efficiency central to their efforts to reduce the emission and harmful impact of carbon dioxide and other greenhouse gases.
Fostering Sustainable Energy
This article discusses the potential scale and benefits of cellulosic ethanol, and presents an analysis of production economics to identify the key process steps that limit cost effectiveness. In particular, the authors flag the initial conversion of biomass into sugars as a key bottleneck requiring new biotechnological solutions to improve efficiency.
Lynd, L.R., M.S. Laser, D. Bransby, B. E. Dale, B. Davison, R. Hamilton, M. Himmel, M. Keller, J.D. McMillan, J. Sheehan, C.E. Wyman, 2008. How biotech can transform biofuels. Nature Biotechnology, 26(2):169-172.
Positive Impact on Global Climate Change
In this recent paper from the Proceedings of the National Academy of Sciences, the authors find that cellulosic ethanol offers both climate change benefits, primarily due to reduced carbon emissions, and health benefits resulting from lower particulate emissions.
Hill et al., 2009. Climate change and health costs of air emissions from biofuels and gasoline. PNAS 106:2077-2082.
The following United States Department of Energy site presents a summary of life cycle greenhouse gas emissions for both first and second-generation ethanol processes in comparison to gasoline. Links are provided to pages that go into more detail on energy balance, emissions, and environmental benefits.
The Food versus Fuel Dilemma
In this press release, Michigan State University professor and biofuels expert Bruce Dale makes the case for cellulosic ethanol as a means to produce biofuel while avoiding competition with food production.
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