American Chemical Society

Toward a more economical process for making biodiesel fuel from algae

Scientists today described an advance toward a long-sought economical process that could turn algae, like the stuff of pond scum, into a revolutionary new and sustainable source of biodiesel and other "green" fuels. Their report on the use of an environmentally friendly process for extracting oil from algae came at a session of 16th annual Green Chemistry & Engineering Conference, being held here June 18-20 by the Green Chemistry Institute, part of the American Chemical Society (ACS), the world's largest scientific society.

"Algae has great promise as a next-generation biofuel, a fuel that is sustainable and renewable," explained Julie Zimmerman, Ph.D., who leads the research team. "It has more oil per pound than corn and soybeans, does not divert crops from the food supply and can potentially be grown in sewage water and seawater without impacting the freshwater supply." The presentation was part of a symposium on green fuel sources, abstracts for which appear below.

Lindsay Soh, a graduate student in Zimmerman's lab, described their efforts toward a simple process that would extract the fatty molecules called lipids used to make biodiesel from algae and transform them into usable fuel in one fell swoop. This could make biodiesel production from algae cheaper, faster and greener than current methods, which require separate steps — each with its own vessel and chemicals — to perform those operations. This "one-pot" reaction uses so-called supercritical carbon dioxide, which uses elevated pressures and temperatures so that it fills its container like a gas but is as dense as a liquid.

Zimmerman pointed out that supercritical carbon dioxide has long had a variety of commercial and industrial uses, ranging from a process used to decaffeinate coffee to a more environmentally friendly solvent for dry cleaning clothing. The process is nontoxic, which makes it an attractive alternative to some of the harsher, potentially toxic chemicals used in other algae-to-biofuel technology, she noted.

"But this really is the first time that scientists have realized that a green system like supercritical CO2 might have applications in producing biofuel from algae."

Soh explained that similar approaches have been proposed for using supercritical methanol and ethanol, but the use of supercritical carbon dioxide requires lower temperatures, making it easier to work with and less energy-intensive. Another advantage, Zimmerman noted, is that the supercritical carbon dioxide, which acts as a solvent for oil, can be tuned to extract only specific components from algae oils, saving time and resources. Such tuning is not possible with conventional solvents. Another advantage: Supercritical carbon dioxide is a long-established technology, with an excellent track record in industrial and commercial applications ― something that may smooth its transition from the lab to everyday use.

Zimmerman and Soh already have shown in previous research that supercritical carbon dioxide can extract lipids from algae. Soh now is moving ahead with the next step, which involves converting the lipids to biodiesel, with the ultimate goal of performing the entire extraction and conversion in a single production chamber.

"Combining the processes into a single step is important," Soh explained. "Supercritical carbon dioxide is a pricey technology because it requires a good deal of energy and initial capital. If we can combine this into one step, it will reduce the costs and bring us closer to commercialization."

Transforming the extracted lipids into biodiesel requires a catalyst, a substance that encourages a chemical reaction without being consumed by it. Soh is experimenting with several, focusing on commercially available catalysts that are insoluble in the supercritical carbon dioxide mixture so that they can be recovered after the reaction without additional steps, which take time, money and, frequently, potentially toxic chemicals.


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The ACS Green Chemistry Institute® is an organization focused on catalyzing and enabling the implementation of green chemistry and engineering throughout the global chemical enterprise. ACS GCI operates industrial roundtables; conducts conferences, seminars and training; maintains an international network of 26 green chemistry chapters; and with its partner NSF International, led the effort to establish the first consensus standard for greener chemical products and process information in the United States.

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147 - One-pot algal biodiesel production in supercritical carbon dioxide

Lindsay Soh1, lindsay.soh@yale.edu, Julie Zimmerman1,2. (1) Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06511, United States, (2) School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511, United States

To advance the realization of algae as a feedstock for biodiesel, process technologies and closed-loop biomass use must be optimized. Life-cycle analysis (LCA) of the biodiesel production process highlights the potential significant impact of a more effective single-step lipid extraction and transesterification process. This work investigates the fundamental science necessary to achieve a one-pot approach that both extracts and transesterifies lipid from algae using supercritical carbon dioxide/methanol (scCO2/MeOH) and heterogeneous catalysts. A variety of both basic and acidic heterogeneous catalysts have been surveyed for their effectiveness at transesterification of triglyceride (TAG) to fatty acid methyl esters (FAME). Further the enhanced solubility of FAME over reaction intermediates, TAG, and glycerol, has been shown to provide a driving force for the reaction. This research offers the foundations for a simple one-pot system wherein biodiesel can be directly, selectively, and sustainably produced from algae for further application in an algae biorefinery.

141 - Sustainable production of industrial chemicals using microbial biocatalysts: 1,4-Butanediol

Stephen Van Dien, svandien@genomatica.com, Genomatica, Inc., San Diego, CA, United States

Oil and natural gas are used as the primary raw materials for manufacturing an astonishing array of large volume chemicals, polymers, and other products that improve our overall standard of living. Growing concerns over the environment and volatile fossil energy costs have inspired a quest to develop more sustainable processes that afford these same products from renewable feedstocks with lower cost, energy consumption, and greenhouse gas emissions. Metabolic engineering of microorganisms is a powerful approach to address this need.A recent success story in sustainable chemical process development is Genomatica's production of the industrial chemical 1,4-butanediol (BDO) using engineered strains of Escherichia coli. BDO is a chemical intermediate that goes into a range of products including automotive, electronics and apparels (such as spandex), and is currently only commercially made through energy intensive petrochemical processes from hydrocarbon feedstocks. Nearly three billion pounds per year of this chemical are produced worldwide. Therefore, this product represents an opportunity to make a significant impact on the replacement of traditional petrochemical processes with bioprocesses using renewable feedstocks.Genomatica has established an integrated suite of computational and laboratory technologies to design, create, and optimize novel organisms and bioprocesses. This presentation will cover the application of this integrated technology platform to design, construct, and optimize a high-performing microorganism capable of producing BDO from carbohydrate feedstocks. Genomatica's modeling technology facilitates the design of both host metabolism and the heterologous biopathway. After constructing the organism based on the design, our models facilitated the analysis of fermentation and 'omics' data to evaluate performance, thus finding targets for further rounds of strain engineering. The presentation will show how significant progress was made in BDO titer, production rate, and yield through model-guided strain improvement, ultimately resulting in an economically attractive process that was validated at the pilot and demonstration scale.

142 - Paving the way for renewable chemicals using biosuccinic acid

Goutham N Vemuri, goutham.vemuri@bio-amber.com, Biocatalysis Development, BioAmber, Plymouth, Minnesota 55447, United States

Bio-based succinic acid has emerged to be the C4-platform of interest for the production of renewable chemicals, with applications in food, pharmaceutical and cosmetics. The benign environmental profile, superior economics and the novel performance of bio-based succinic acid in comparison to petroleum-derived succinic acid propel the development of biological processes for the production of succinate and its derivatives.At BioAmber, we are already at the forefront in testing and developing bio-based succinic acid in a variety of applications ranging from polyurethanes, resins, coatings, phthalate-free plasticizers, deicing salts, cosmetics, flavors and fragrances. In all these applications, bio-based succinic acid offered a unique combination of performance, economic and environmental benefits. We are the first in the market with commercial scale production of bio-based succinic acid, and are currently serving customers from our plant in Europe. This plant has been audited and qualified for commercial manufacturing. As a consequence of the market demand, our present capacity increased from 2,000 MT/year to 3,000 MT/year.Additionally, we are also advancing new product platform based on modified polybutylene succinate (mPBS). Through a joint venture with NatureWorks, the leader in bio-plastics, a new family of bio-based polymers blended with mPBS and PLA is available. We have taken advantage of our foundation in the C4 platform to expand our product portfolio to C6 chemicals, notably, adipic acid, bio-caprolactam and bio-hexamethylenediamine. Our proprietary technology platform integrates industrial biotechnology, a novel purification scheme and chemical catalysis to convert renewable feedstocks into value-added chemicals for use in a wide variety of everyday products.

143 - Recombinant cellulolytic bacillus subtilis as the platform for one-step production of biofuels and biochemical from pretreated biomass

Y-H Percival Zhang1, ypzhang@vt.edu, Xiao-Zhou Zhang1, Chun You2, Hui Ma1. (1) Gate Fuels Inc, Blacksburg, VA 24061, United States, (2) Biological Systems Engineering, Virginia Tech, Blacksburg, VA 24061, United States

Consolidated bioprocessing (CBP) is a low-cost cellulosic biomass processing by integrating cellulase production, cellulose hydrolysis, and sugar fermentation into a single step. Although significant efforts have been made to create recombinant cellulolytic microorganisms, real recombinant cellulolytic microorganism that can produce sufficient secretory active cellulases, hydrolyze cellulose, and utilize soluble sugars for supporting cell growth and cellulase synthesis without help of organic nutrients was not available before our efforts. We demonstrated that over-expression of Bacillus subtilis endoglucanase BsCel5 enables non-cellulose-utilizing Bacillus subtilis to grow on cellulose and pretreated lignocellulosic biomass as the sole carbon source without addition of costly organic nutrients. After directed evolution and screen on solid cellulose through a novel powerful and highly efficient enzyme engineering platform, both the expression/secretion level and specific activity of BsCel5 has been increased successfully. We also optimized and co-expressed secretory family 5, 9 and 48 cellulases in a single B. subtilis strain. One-step production of ethanol, micro-biodiesel and lactate from cellulose and pretreated biomass in the minimal medium without adding any organic nutrient has been demonstrated. The recombinant cellulolytic B. subtilis would be an ultra-low-cost platform for producing biofuels (e.g., ethanol, butanol, fatty alcohols) and other value-added products (e.g., lactate, fumaric acid) from non-food biomass, with obvious advantages over other developing CBP microorganisms.

144 - Methacrylated lignin model compounds as monomers for use in high-performance polymers

Joseph F Stanzione1, jfstanz@udel.edu, Joshua M Sadler2, John J La Scala2, Richard P Wool1. (1) Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, United States, (2) RDRL-WMM-C, Army Research Laboratory, Aberdeen Proving Ground, MD 21005, United States

Lignin is a copious pulp and paper industry waste product that has the potential to be a vital next-generation biorefinery feedstock that could yield valuable macromolecular and low molecular weight aromatic chemicals when strategically depolymerized. The high aromatic content found in lignin would be ideal for the development of high-performance, bio-based polymers for a wide range of applications since the incorporation of aromaticity to the chemical structure of a polymer is known to drastically improve its strength and increase its glass transition temperature. Methacrylated lignin model compounds synthesized and employed as alternative, bio-based monomers for use in high-performance polymers are presented. Specifically, methacrylated versions of vanillin, guaiacol, eugenol, phenol, creosol, 4-propylguaiacol, catechol, and 4-methylcatechol were incorporated either individually as potential styrene replacements or as mixtures into vinyl ester resins. Monomer properties as well as structure- property relationships of the resins and polymers are also presented.

145 - Ionic liquids in integrated catalytic technologies to produce furanic chemicals

Anders Riisager1, ar@kemi.dtu.dk, Tim Ståhlberg1, Wenjing Fu2, John M Woodley2, Peter Fristrup1. (1) Centre for Catalysis and Sustainable Chemistry, Department of Chemistry, Technical University of Denmark, Kgs. Lyngby, Denmark, (2) Center for BioProcess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark

A renewable chemical industry must be based on biomass as the only abundant carbon source. The acid-catalyzed dehydration of hexoses (e.g. glucose, fructose or their polymers) yields 5-hydroxymethylfurfural (HMF). HMF is an intermediate that potentially can be converted into a range of value-added chemicals applicable as, for example, solvents, polymer monomers and fuel additives by catalytic isomerization, oxidation or hydrogenation. In this context an important future direction is to develop integrated technologies which facilitate multistep catalytic synthesis and combined reactions without intermediate recovery steps. Such methods may increase space-time-yield and reduce operational costs through minimized expenditure of supplementary chemicals and energy. This presentation will highlight results obtained in catalytic conversion of hexoses to furanic chemicals in ionic liquids with integrated process technologies combining bio- and chemo-catalysis and modes of operation.

146 - Renewable oils for bio-based chemicals

Timothy Dummer, ctravis@solazyme.com, Department of Fuels and Chemicals, Solazyme, Inc., South San Francisco, CA 94080, United States

Solazyme is a renewable oil and bioproducts company, harnessing the power of microalgae to produce clean and scalable oils for four key markets: fuels, chemicals, nutrition and skin and personal care. Well beyond proof-of-concept, Solazyme is entering into a commercial phase, producing hundreds of thousands of liters of algal oil through a proprietary, scalable process that transforms carbohydrate feedstocks into renewable triglyceride oils. Solazyme's core technology utilizes microalgae to transform carbohydrate feedstocks into fatty acids in the triglyceride form. These triglyceride oils can then be converted through biological or chemical routes to numerous value-added chemicals, such as surfactants, lubricants and polymers in existing industry infrastructure. Solazyme has developed a valuable, unique and proprietary industry-leading microbial chemicals platform, which exploits designer triglyceride oils as the basis for the next generation of high performance bio-based fluids and green chemicals. Through partnerships with industry leading chemical companies including Dow and Unilever, Solazyme is proving high value sustainable and renewable products, tailored to specific market needs that are independent of natural oil supply-demand volatility. In this presentation, we will discuss how and why Solazyme's renewable chemicals platform expands the possibilities for further replacements of petroleum derived oils with renewable, sustainable alternatives.

148 - The search for cost competitive cellulosic sugars

Fred Moesler, sarah@antennagroup.com, Renmatix, United States

Renmatix produces industrial sugars, the cornerstone of the $150B and fast growing global renewable fuels and chemical markets. Fuels from abundant, domestically sourced renewable materials hold great promise. Similarly, biochemical producers require affordable sugars as the petroleum-replacement for many basic chemicals; yet, little progress has been made in achieving large-scale production. The challenge: unlocking the sugars inherent in biomass at a cost point that will enable the industry to compete on an economic basis with petroleum derived products. These intermediate chemicals can then be used to make everything from plastic bottles, paints, tennis shoes, and tires.Using supercritical water—water at elevated pressures and temperatures—Renmatix is able to deconstruct a wide range of non-food biomass in seconds. The water-based process uses no significant consumables and produces much of its own process energy. Current methods of breaking down biomass—enzymatic or acid hydrolysis—require expensive enzymes or harsh chemicals, and can take up to three days to yield sugars. With significant advantages in cost and speed, Renmatix is able to provide cellulosic sugar affordably and on large-scale from feedstocks like wood and agricultural waste.In this session, Renmatix VP of Technology Fred Moesler will discuss how supercritical hydrolysis provides a low cost alternative to traditional biomass-to-sugar conversion methods. Supercritical hydrolysis is comprised of two distinct steps: hemi-hydrolysis and cellulose-hydrolysis, producing separate C5 (xylose) and C6 (glucose) sugar streams. While supercritical liquids have an established history in industrial processes, such as coffee decaffeination and pharmaceutical applications, Renmatix is the first company to successfully yield sugar from biomass at significant scale. Already scaled 3000x in the past three years, Renmatix's process has attracted an impressive technical, executive, and investor team to drive commercialization. A commercial facility with annual production capacity of 100,000 tons of sugar is scheduled to break ground in 2012.