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1

Laccase applications in biofuels production: current status and future prospects.  

PubMed

The desire to reduce dependence on the ever diminishing fossil fuel reserves coupled with the impetus towards green energy has seen increased research in biofuels as alternative sources of energy. Lignocellulose materials are one of the most promising feedstocks for advanced biofuels production. However, their utilisation is dependent on the efficient hydrolysis of polysaccharides, which in part is dependent on cost-effective and benign pretreatment of biomass to remove or modify lignin and release or expose sugars to hydrolytic enzymes. Laccase is one of the enzymes that are being investigated not only for potential use as pretreatment agents in biofuel production, mainly as a delignifying enzyme, but also as a biotechnological tool for removal of inhibitors (mainly phenolic) of subsequent enzymatic processes. The current review discusses the major advances in the application of laccase as a potential pretreatment strategy, the underlying principles as well as directions for future research in the search for better enzyme-based technologies for biofuel production. Future perspectives could include synergy between enzymes that may be required for optimal results and the adoption of the biorefinery concept in line with the move towards the global implementation of the bioeconomy strategy. PMID:24841120

Kudanga, Tukayi; Le Roes-Hill, Marilize

2014-08-01

2

Biofuels and biodiversity: principles for creating better policies for biofuel production.  

PubMed

Biofuels are a new priority in efforts to reduce dependence on fossil fuels; nevertheless, the rapid increase in production of biofuel feedstock may threaten biodiversity. There are general principles that should be used in developing guidelines for certifying biodiversity-friendly biofuels. First, biofuel feedstocks should be grown with environmentally safe and biodiversity-friendly agricultural practices. The sustainability of any biofuel feedstock depends on good growing practices and sound environmental practices throughout the fuel-production life cycle. Second, the ecological footprint of a biofuel, in terms of the land area needed to grow sufficient quantities of the feedstock, should be minimized. The best alternatives appear to be fuels of the future, especially fuels derived from microalgae. Third, biofuels that can sequester carbon or that have a negative or zero carbon balance when viewed over the entire production life cycle should be given high priority. Corn-based ethanol is the worst among the alternatives that are available at present, although this is the biofuel that is most advanced for commercial production in the United States. We urge aggressive pursuit of alternatives to corn as a biofuel feedstock. Conservation biologists can significantly broaden and deepen efforts to develop sustainable fuels by playing active roles in pursuing research on biodiversity-friendly biofuel production practices and by helping define biodiversity-friendly biofuel certification standards. PMID:18261147

Groom, Martha J; Gray, Elizabeth M; Townsend, Patricia A

2008-06-01

3

Production of biofuels from microalgae  

Microsoft Academic Search

The production of biofuels from microalgae, especially biodiesel, has become a topic of great interest in recent years. However,\\u000a many of the published papers do not consider the question of scale up and the feasibility of the various processes to be operated\\u000a at the very large scale required if algal biofuels are to make a meaningful contribution to renewable fuels.

Sophie Fon Sing; Andreas Isdepsky; Michael A. Borowitzka; Navid Reza Moheimani

4

WATER IMPLICATIONS OF BIOFUELS PRODUCTION  

EPA Science Inventory

Presentation requested by the National Academy of Science (NAS) for a Colloquium on Water Quality Implications of Biofuels Production, to be held at the NAS in Washington, D.C. on July 12, 2007. This presentation will address the influence of ethanol on hydrocarbon plumes and th...

5

Biofuels Fuels Technology Pathway Options for Advanced Drop-In Biofuels Production.  

National Technical Information Service (NTIS)

Advanced drop-in hydrocarbon biofuels require biofuel alternatives for refinery products other than gasoline. Candidate biofuels must have performance characteristics equivalent to conventional petroleum-based fuels. The technology pathways for biofuel al...

K. L. Kenney

2011-01-01

6

Toward nitrogen neutral biofuel production.  

PubMed

Environmental concerns and an increasing global energy demand have spurred scientific research and political action to deliver large-scale production of liquid biofuels. Current biofuel processes and developing approaches have focused on closing the carbon cycle by biological fixation of atmospheric carbon dioxide and conversion of biomass to fuels. To date, these processes have relied on fertilizer produced by the energy-intensive Haber-Bosch process, and have not addressed the global nitrogen cycle and its environmental implications. Recent developments to convert protein to fuel and ammonia may begin to address these problems. In this scheme, recycling ammonia to either plant or algal feedstocks reduces the demand for synthetic fertilizer supplementation. Further development of this technology will realize its advantages of high carbon fixation rates, inexpensive and simple feedstock processing, in addition to reduced fertilizer requirements. PMID:22054644

Huo, Yi-Xin; Wernick, David G; Liao, James C

2012-06-01

7

Towards Sustainable Production of Biofuels from Microalgae  

PubMed Central

Renewable and carbon neutral biofuels are necessary for environmental and economic sustainability. The viability of the first generation biofuels production is however questionable because of the conflict with food supply. Microalgal biofuels are a viable alternative. The oil productivity of many microalgae exceeds the best producing oil crops. This paper aims to analyze and promote integration approaches for sustainable microalgal biofuel production to meet the energy and environmental needs of the society. The emphasis is on hydrothermal liquefaction technology for direct conversion of algal biomass to liquid fuel.

Patil, Vishwanath; Tran, Khanh-Quang; Giselr?d, Hans Ragnar

2008-01-01

8

Multiphase Flow Modeling of Biofuel Production Processes  

SciTech Connect

As part of the Idaho National Laboratory's (INL's) Secure Energy Initiative, the INL is performing research in areas that are vital to ensuring clean, secure energy supplies for the future. The INL Hybrid Energy Systems Testing (HYTEST) Laboratory is being established to develop and test hybrid energy systems with the principal objective to safeguard U.S. Energy Security by reducing dependence on foreign petroleum. HYTEST involves producing liquid fuels in a Hybrid Energy System (HES) by integrating carbon-based (i.e., bio-mass, oil-shale, etc.) with non-carbon based energy sources (i.e., wind energy, hydro, geothermal, nuclear, etc.). Advances in process development, control and modeling are the unifying vision for HES. This paper describes new modeling tools and methodologies to simulate advanced energy processes. Needs are emerging that require advanced computational modeling of multiphase reacting systems in the energy arena, driven by the 2007 Energy Independence and Security Act, which requires production of 36 billion gal/yr of biofuels by 2022, with 21 billion gal of this as advanced biofuels. Advanced biofuels derived from microalgal biomass have the potential to help achieve the 21 billion gal mandate, as well as reduce greenhouse gas emissions. Production of biofuels from microalgae is receiving considerable interest due to their potentially high oil yields (around 600 gal/acre). Microalgae have a high lipid content (up to 50%) and grow 10 to 100 times faster than terrestrial plants. The use of environmentally friendly alternatives to solvents and reagents commonly employed in reaction and phase separation processes is being explored. This is accomplished through the use of hydrothermal technologies, which are chemical and physical transformations in high-temperature (200-600 C), high-pressure (5-40 MPa) liquid or supercritical water. Figure 1 shows a simplified diagram of the production of biofuels from algae. Hydrothermal processing has significant advantages over other biomass processing methods with respect to separations. These 'green' alternatives employ a hybrid medium that, when operated supercritically, offers the prospect of tunable physicochemical properties. Solubility can be rapidly altered and phases partitioned selectively to precipitate or dissolve certain components by altering temperature or pressure in the near-critical region. The ability to tune the solvation properties of water in the highly compressible near-critical region facilitates partitioning of products or by-products into separate phases to separate and purify products. Since most challenges related to lipid extraction are associated with the industrial scale-up of integrated extraction systems, the new modeling capability offers the prospect of addressing previously untenable scaling issues.

D. Gaston; D. P. Guillen; J. Tester

2011-06-01

9

Coupling of Algal Biofuel Production with Wastewater  

PubMed Central

Microalgae have gained enormous consideration from scientific community worldwide emerging as a viable feedstock for a renewable energy source virtually being carbon neutral, high lipid content, and comparatively more advantageous to other sources of biofuels. Although microalgae are seen as a valuable source in majority part of the world for production of biofuels and bioproducts, still they are unable to accomplish sustainable large-scale algal biofuel production. Wastewater has organic and inorganic supplements required for algal growth. The coupling of microalgae with wastewater is an effective way of waste remediation and a cost-effective microalgal biofuel production. In this review article, we will primarily discuss the possibilities and current scenario regarding coupling of microalgal cultivation with biofuel production emphasizing recent progress in this area.

Panwar, Amit; Bisht, Tara Singh; Tamta, Sushma

2014-01-01

10

Biofuels  

NASA Astrophysics Data System (ADS)

The principal types of biofuels that can be obtained from biorenewable energy sources are analyzed. As these sources, various sorts of biomass, which is accumulated upon photosynthetic conversion of solar energy, are considered. A typical feature of biofuel production is combination of chemical and biotechnological approaches.

Varfolomeev, Sergei D.; Efremenko, E. N.; Krylova, Larisa P.

2010-08-01

11

Potential of biofilm-based biofuel production  

Microsoft Academic Search

Biofilm technology has been extensively applied to wastewater treatment, but its potential application in biofuel production\\u000a has not been explored. Current technologies of converting lignocellulose materials to biofuel are hampered by costly processing\\u000a steps in pretreatment, saccharification, and product recovery. Biofilms may have a potential to improve efficiency of these\\u000a processes. Advantages of biofilms include concentration of cell-associated hydrolytic enzymes

Zhi-Wu Wang; Shulin Chen

2009-01-01

12

Future Testing Opportunities to Ensure Sustainability of the Biofuels Industry  

Microsoft Academic Search

For the soil and plant analysis community, development and expansion of biofuels will create many opportunities to provide a wide variety of analytical services. Our objective is to explore potential areas where those services could be marketed to support sustainable development of biofuels. One of the first is to provide soil fertility and plant nutrition information for sustainable feedstock production.

Douglas L. Karlen; Brian J. Kerr

2012-01-01

13

A literature review of the market effects of federal biofuel policy and recommendations for future policy  

NASA Astrophysics Data System (ADS)

The United States has had a federal biofuels policy since the 1970s. The purpose of this policy was to help the development of a biofuel industry during a time of high fuel prices in order to provide a domestic alternative to expensive foreign oil. Later the policy was changed to help lower the environmental impact caused by conventional fuels. Since that time the industry has grown and currently produces around 15 billion gallons of biofuels every year. The current federal biofuel policy is largely based on one program, the Renewable Fuel Standard (RFS), which mandates the production and blending of several different classes of biofuels and provides a form of subsidy to the biofuel industry. This paper examines the market effects of the federal biofuel policy and provides recommendations for improving the policy to counteract any negative effects. Federal biofuel policy has many far-reaching market effects. Some are easily calculable through expenditures and lost revenues, while others are harder to quantify because their full effects are not yet known. By evaluating these market effects, this paper will provide ample evidence that the federal biofuels policy needs to change, and will show what effects these changes could induce. The biofuels industry largely owes its existence to government policies, however as the research shows the industry can now stand on its own. This paper will examine what will happen if the federal policy is eliminated and what the future of the biofuels industry could hold. Based on these examinations, it is unlikely that the industry needs further government support and policies should be adjusted in light of this.

Ayers, Alex Elgin

14

Dual role of microalgae: Phycoremediation of domestic wastewater and biomass production for sustainable biofuels production  

Microsoft Academic Search

Global threats of fuel shortages in the near future and climate change due to green-house gas emissions are posing serious challenges and hence and it is imperative to explore means for sustainable ways of averting the consequences. The dual application of microalgae for phycoremediation and biomass production for sustainable biofuels production is a feasible option. The use of high rate

I. Rawat; R. Ranjith Kumar; T. Mutanda; F. Bux

2011-01-01

15

Challenges in engineering microbes for biofuels production.  

PubMed

Economic and geopolitical factors (high oil prices, environmental concerns, and supply instability) have been prompting policy-makers to put added emphasis on renewable energy sources. For the scientific community, recent advances, embodied in new insights into basic biology and technology that can be applied to metabolic engineering, are generating considerable excitement. There is justified optimism that the full potential of biofuel production from cellulosic biomass will be obtainable in the next 10 to 15 years. PMID:17289987

Stephanopoulos, Gregory

2007-02-01

16

A Survey of Biofuel Production potentials in Russia  

NASA Astrophysics Data System (ADS)

Due to the abundance of fossil fuel resources in Russia, the development of the renewable energy market there was delayed. Recent technological advancement has led to an increasing interest in biofuel production. The aim of research was to evaluate how biofuels are introduced into the current energy scheme of the country. The potential production of biofuels was estimated based on sustainable approaches which provide solution for carbon emission reduction and environmental benefits. Russia still requires biofuel policy to make biofuels compatible with traditional fossil fuels.

Lykova, Natalya; Gustafsson, Jan-Erik

2010-01-01

17

Biofuels Fuels Technology Pathway Options for Advanced Drop-in Biofuels Production  

SciTech Connect

Advanced drop-in hydrocarbon biofuels require biofuel alternatives for refinery products other than gasoline. Candidate biofuels must have performance characteristics equivalent to conventional petroleum-based fuels. The technology pathways for biofuel alternatives also must be plausible, sustainable (e.g., positive energy balance, environmentally benign, etc.), and demonstrate a reasonable pathway to economic viability and end-user affordability. Viable biofuels technology pathways must address feedstock production and environmental issues through to the fuel or chemical end products. Potential end products include compatible replacement fuel products (e.g., gasoline, diesel, and JP8 and JP5 jet fuel) and other petroleum products or chemicals typically produced from a barrel of crude. Considering the complexity and technology diversity of a complete biofuels supply chain, no single entity or technology provider is capable of addressing in depth all aspects of any given pathway; however, all the necessary expert entities exist. As such, we propose the assembly of a team capable of conducting an in-depth technology pathway options analysis (including sustainability indicators and complete LCA) to identify and define the domestic biofuel pathways for a Green Fleet. This team is not only capable of conducting in-depth analyses on technology pathways, but collectively they are able to trouble shoot and/or engineer solutions that would give industrial technology providers the highest potential for success. Such a team would provide the greatest possible down-side protection for high-risk advanced drop-in biofuels procurement(s).

Kevin L Kenney

2011-09-01

18

Cyanobacteria as a Platform for Biofuel Production  

PubMed Central

Cyanobacteria have great potential as a platform for biofuel production because of their fast growth, ability to fix carbon dioxide gas, and their genetic tractability. Furthermore they do not require fermentable sugars or arable land for growth and so competition with cropland would be greatly reduced. In this perspective we discuss the challenges and areas for improvement most pertinent for advancing cyanobacterial fuel production, including: improving genetic parts, carbon fixation, metabolic flux, nutrient requirements on a large scale, and photosynthetic efficiency using natural light.

Nozzi, Nicole E.; Oliver, John W. K.; Atsumi, Shota

2013-01-01

19

Limitation of Biofuel Production in Europe from the Forest Market  

NASA Astrophysics Data System (ADS)

The European Union has set a 10% target for the share of biofuel in the transportation sector to be met by 2020. To reach this target, second generation biofuel is expected to replace 3 to 5% of the transport fossil fuel consumption. But the competition on the feedstock is an issue and makes the planning for the second generation biofuel plant a challenge. Moreover, no commercial second generation biofuel production plant is under operation, but if reaching commercial status, this type of production plants are expected to become very large. In order to minimize the tranportation costs and to takle the competetion for the feedstock against the existing woody based industries, the geographical location of biofuel production plants becomes an issue. This study investigates the potential of second generation biofuel economically feasible in Europe by 2020 in regards with the competition for the feedsstock with the existing woody biomass based industries (CHP, pulp and paper mills, sawmills...). To assess the biofuel potential in Europe, a techno-economic, geographically explicit model, BeWhere, is used. It determines the optimal locations of bio-energy production plants by minimizing the costs and CO2 emissions of the entire supply chain. The existing woody based industries have to first meet their wood demand, and if the amount of wood that remains is suficiant, new bio-energy production plants if any can be set up. Preliminary results show that CHP plants are preferably chosen over biofuel production plants. Strong biofuel policy support is needed in order to consequently increase the biofuel production in Europe. The carbon tax influences the emission reduction to a higher degree than the biofuel support. And the potential of second generation biofuel would at most reach 3% of the European transport fuel if the wood demand does not increase from 2010.

Leduc, Sylvain; Wetterlund, Elisabeth; Dotzauer, Erik; Kindermann, Georg

2013-04-01

20

Metabolic Engineering for Advanced Biofuels Production from Escherichia coli  

PubMed Central

Summary Global energy and environmental problems have stimulated increasing efforts towards synthesizing liquid biofuels as transportation energy. Compared to the traditional biofuel, ethanol, advanced biofuels should offer advantages such as higher energy density, lower hygroscopicity, lower vapor pressure, and compatibility with existing transportation infrastructure. However, these fuels are not synthesized economically using native organisms. Metabolic engineering offers an alternative approach in which synthetic pathways are engineered into user friendly hosts for the production of these fuel molecules. These hosts could be readily manipulated to improve the production efficiency. This review summarizes recent progress in the engineering of Escherichia coli to produce advanced biofuels.

Atsumi, Shota; Liao, James C.

2008-01-01

21

Metabolic engineering of microbial pathways for advanced biofuels production.  

PubMed

Production of biofuels from renewable resources such as cellulosic biomass provides a source of liquid transportation fuel to replace petroleum-based fuels. This endeavor requires the conversion of cellulosic biomass into simple sugars, and the conversion of simple sugars into biofuels. Recently, microorganisms have been engineered to convert simple sugars into several types of biofuels, such as alcohols, fatty acid alkyl esters, alkanes, and terpenes, with high titers and yields. Here, we review recently engineered biosynthetic pathways from the well-characterized microorganisms Escherichia coli and Saccharomyces cerevisiae for the production of several advanced biofuels. PMID:21620688

Zhang, Fuzhong; Rodriguez, Sarah; Keasling, Jay D

2011-12-01

22

Biofuels  

NASA Video Gallery

Whatâ??s green, slimy and packed full of energy? Algae, of course! This biofuel is just one of the many renewable energies NASA studies. Biofuels could generate and store energy for long-term human...

23

Wastewater treatment high rate algal ponds for biofuel production  

Microsoft Academic Search

While research and development of algal biofuels are currently receiving much interest and funding, they are still not commercially viable at today’s fossil fuel prices. However, a niche opportunity may exist where algae are grown as a by-product of high rate algal ponds (HRAPs) operated for wastewater treatment. In addition to significantly better economics, algal biofuel production from wastewater treatment

J. B. K. Park; R. J. Craggs; A. N. Shilton

2011-01-01

24

Rapid saccharification for production of cellulosic biofuels.  

PubMed

The economical production of biofuels is hindered by the recalcitrance of lignocellulose to processing, causing high consumption of processing enzymes and impeding hydrolysis of pretreated lignocellulosic biomass. We determined the major rate-limiting factor in the hydrolysis of popping pre-treated rice straw (PPRS) by examining cellulase adsorption to lignin and cellulose, amorphogenesis of PPRS, and re-hydrolysis. Based on the results, equivalence between enzyme loading and the open structural area of cellulose was required to significantly increase productive adsorption of cellulase and to accelerate enzymatic saccharification of PPRS. Amorphogenesis of PPRS by phosphoric acid treatment to expand open structural area of the cellulose fibers resulted in twofold higher cellulase adsorption and increased the yield of the first re-hydrolysis step from 13% to 46%. The total yield from PPRS was increased to 84% after 3h. These results provide evidence that cellulose structure is one of major effects on the enzymatic hydrolysis. PMID:24607460

Lee, Dae-Seok; Wi, Seung Gon; Lee, Soo Jung; Lee, Yoon-Gyo; Kim, Yeong-Suk; Bae, Hyeun-Jong

2014-04-01

25

Genetically Engineered Materials for Biofuels Production  

NASA Astrophysics Data System (ADS)

Agrivida, Inc., is an agricultural biotechnology company developing industrial crop feedstocks for the fuel and chemical industries. Agrivida's crops have improved processing traits that enable efficient, low cost conversion of the crops' cellulosic components into fermentable sugars. Currently, pretreatment and enzymatic conversion of the major cell wall components, cellulose and hemicellulose, into fermentable sugars is the most expensive processing step that prevents widespread adoption of biomass in biofuels processes. To lower production costs we are consolidating pretreatment and enzyme production within the crop. In this strategy, transgenic plants express engineered cell wall degrading enzymes in an inactive form, which can be reactivated after harvest. We have engineered protein elements that disrupt enzyme activity during normal plant growth. Upon exposure to specific processing conditions, the engineered enzymes are converted into their active forms. This mechanism significantly lowers pretreatment costs and enzyme loadings (>75% reduction) below those currently available to the industry.

Raab, Michael

2012-02-01

26

Optimizing root system architecture in biofuel crops for sustainable energy production and soil carbon sequestration  

PubMed Central

Root system architecture (RSA) describes the dynamic spatial configuration of different types and ages of roots in a plant, which allows adaptation to different environments. Modifications in RSA enhance agronomic traits in crops and have been implicated in soil organic carbon content. Together, these fundamental properties of RSA contribute to the net carbon balance and overall sustainability of biofuels. In this article, we will review recent data supporting carbon sequestration by biofuel crops, highlight current progress in studying RSA, and discuss future opportunities for optimizing RSA for biofuel production and soil carbon sequestration.

To, Jennifer PC; Zhu, Jinming; Benfey, Philip N

2010-01-01

27

Next-generation biomass feedstocks for biofuel production  

PubMed Central

The development of second-generation biofuels - those that do not rely on grain crops as inputs - will require a diverse set of feedstocks that can be grown sustainably and processed cost-effectively. Here we review the outlook and challenges for meeting hoped-for production targets for such biofuels in the United States.

Simmons, Blake A; Loque, Dominique; Blanch, Harvey W

2008-01-01

28

The potential of sustainable algal biofuel production using wastewater resources  

Microsoft Academic Search

The potential of microalgae as a source of renewable energy has received considerable interest, but if microalgal biofuel production is to be economically viable and sustainable, further optimization of mass culture conditions are needed. Wastewaters derived from municipal, agricultural and industrial activities potentially provide cost-effective and sustainable means of algal growth for biofuels. In addition, there is also potential for

Jon K. Pittman; Andrew P. Dean; Olumayowa Osundeko

2011-01-01

29

Integrated microbial processes for biofuels and high value-added products: the way to improve the cost effectiveness of biofuel production.  

PubMed

The production of microbial biofuels is currently under investigation, as they are alternative sources to fossil fuels, which are diminishing and their use has a negative impact on the environment. However, so far, biofuels derived from microbes are not economically competitive. One way to overcome this bottleneck is the use of microorganisms to transform substrates into biofuels and high value-added products, and simultaneously taking advantage of the various microbial biomass components to produce other products of interest, as an integrated process. In this way, it is possible to maximize the economic value of the whole process, with the desired reduction of the waste streams produced. It is expected that this integrated system makes the biofuel production economically sustainable and competitive in the near future. This review describes the investigation on integrated microbial processes (based on bacteria, yeast, and microalgal cultivations) that have been experimentally developed, highlighting the importance of this approach as a way to optimize microbial biofuel production process. PMID:24337249

da Silva, Teresa Lopes; Gouveia, Luísa; Reis, Alberto

2014-02-01

30

Trojan Horse Strategy for Deconstruction of Biomass for Biofuels Production.  

National Technical Information Service (NTIS)

Production of renewable biofuels to displace fossil fuels currently consumed in the transportation sector is a pressing multiagency national priority (DOE/USDA/EERE). Currently, nearly all fuel ethanol is produced from corn-derived starch. Dedicated energ...

B. Simmons E. Yu J. Timlin M. Hadi M. Sinclair M. Tran-Gyamfi

2011-01-01

31

Feasibilities of consolidated bioprocessing microbes: from pretreatment to biofuel production.  

PubMed

Lignocelluloses are rich sugar treasures, which can be converted to useful commodities such as biofuel with the help of efficient combination of enzymes and microbes. Although several bioprocessing approaches have been proposed, biofuel production from lignocelluloses is limited because of economically infeasible technologies for pretreatment, saccharification and fermentation. Use of consolidated bioprocessing (CBP) microbes is the most promising method for the cost-effective production of biofuels. However, lignocelluloses are obtained from highly diverse environment and hence are heterogeneous in nature. Therefore, it is necessary to develop and integrate tailor-designed pretreatment processes and efficient microbes that can thrive on many different kinds of biomass. In this review, the progress towards the construction of consolidated bioprocessing microbes, which can efficiently convert heterogeneous lignocellulosic biomass to bioenergy, has been discussed; in addition, the potential and constraints of current bioprocessing technologies for cellulosic biofuel production have been discussed. PMID:24745899

Parisutham, Vinuselvi; Kim, Tae Hyun; Lee, Sung Kuk

2014-06-01

32

Exergy-based efficiency and renewability assessment of biofuel production.  

PubMed

This study presents an efficiency and renewability analysis of the production of three biofuels: rapeseed methyl ester (RME), soybean methyl ester (SME) and corn-based ethanol (EtOH). The overall production chains have been taken into account: not only the agricultural crop production and the industrial conversion into biofuel, but also production of the supply of agricultural resources (pesticides, fertilizers, fuel, seeding material) and industrial resources (energy and chemicals) to transform the crops into biofuel. Simultaneously, byproducts of the agricultural and industrial processes have been taken into account when resources have to be allocated to the biofuels. The technical analysis via the second law of thermodynamics revealed that corn-based EtOH results in the highest production rate with an exergetic fuel content of 68.8 GJ ha(-1) yr(-1), whereas the RME and SME results were limited to 47.5 and 16.4 GJ ha(-1) yr(-1). The allocated nonrenewable resource input to deliver these biofuels is significant: 16.5, 15.4, and 5.6 MJ ha(-1) yr(-1). This means that these biofuels, generally considered as renewable resources, embed a nonrenewable fraction of one-quarter for EtOH and even one-third for RME and SME. This type of analysis provides scientifically sound quantitative information that is necessarywith respect to the sustainability analysis of so-called renewable energy. PMID:15952399

Dewulf, J; Van Langenhove, H; Van De Velde, B

2005-05-15

33

Microbial engineering for the production of advanced biofuels.  

PubMed

Advanced biofuels produced by microorganisms have similar properties to petroleum-based fuels, and can 'drop in' to the existing transportation infrastructure. However, producing these biofuels in yields high enough to be useful requires the engineering of the microorganism's metabolism. Such engineering is not based on just one specific feedstock or host organism. Data-driven and synthetic-biology approaches can be used to optimize both the host and pathways to maximize fuel production. Despite some success, challenges still need to be met to move advanced biofuels towards commercialization, and to compete with more conventional fuels. PMID:22895337

Peralta-Yahya, Pamela P; Zhang, Fuzhong; del Cardayre, Stephen B; Keasling, Jay D

2012-08-16

34

Advanced biofuel production by the yeast Saccharomyces cerevisiae.  

PubMed

Replacement of conventional transportation fuels with biofuels will require production of compounds that can cover the complete fuel spectrum, ranging from gasoline to kerosene. Advanced biofuels are expected to play an important role in replacing fossil fuels because they have improved properties compared with ethanol and some of these may have the energy density required for use in heavy duty vehicles, ships, and aviation. Moreover, advanced biofuels can be used as drop-in fuels in existing internal combustion engines. The yeast cell factory Saccharomyces cerevisiae can be turned into a producer of higher alcohols (1-butanol and isobutanol), sesquiterpenes (farnesene and bisabolene), and fatty acid ethyl esters (biodiesel), and here we discusses progress in metabolic engineering of S. cerevisiae for production of these advanced biofuels. PMID:23628723

Buijs, Nicolaas A; Siewers, Verena; Nielsen, Jens

2013-06-01

35

Enzymatic deconstruction of xylan for biofuel production  

PubMed Central

The combustion of fossil-derived fuels has a significant impact on atmospheric carbon dioxide (CO2) levels and correspondingly is an important contributor to anthropogenic global climate change. Plants have evolved photosynthetic mechanisms in which solar energy is used to fix CO2 into carbohydrates. Thus, combustion of biofuels, derived from plant biomass, can be considered a potentially carbon neutral process. One of the major limitations for efficient conversion of plant biomass to biofuels is the recalcitrant nature of the plant cell wall, which is composed mostly of lignocellulosic materials (lignin, cellulose, and hemicellulose). The heteropolymer xylan represents the most abundant hemicellulosic polysaccharide and is composed primarily of xylose, arabinose, and glucuronic acid. Microbes have evolved a plethora of enzymatic strategies for hydrolyzing xylan into its constituent sugars for subsequent fermentation to biofuels. Therefore, microorganisms are considered an important source of biocatalysts in the emerging biofuel industry. To produce an optimized enzymatic cocktail for xylan deconstruction, it will be valuable to gain insight at the molecular level of the chemical linkages and the mechanisms by which these enzymes recognize their substrates and catalyze their reactions. Recent advances in genomics, proteomics, and structural biology have revolutionized our understanding of the microbial xylanolytic enzymes. This review focuses on current understanding of the molecular basis for substrate specificity and catalysis by enzymes involved in xylan deconstruction.

DODD, DYLAN; CANN, ISAAC K. O.

2010-01-01

36

Enzymatic deconstruction of xylan for biofuel production.  

PubMed

The combustion of fossil-derived fuels has a significant impact on atmospheric carbon dioxide (CO(2)) levels and correspondingly is an important contributor to anthropogenic global climate change. Plants have evolved photosynthetic mechanisms in which solar energy is used to fix CO(2) into carbohydrates. Thus, combustion of biofuels, derived from plant biomass, can be considered a potentially carbon neutral process. One of the major limitations for efficient conversion of plant biomass to biofuels is the recalcitrant nature of the plant cell wall, which is composed mostly of lignocellulosic materials (lignin, cellulose, and hemicellulose). The heteropolymer xylan represents the most abundant hemicellulosic polysaccharide and is composed primarily of xylose, arabinose, and glucuronic acid. Microbes have evolved a plethora of enzymatic strategies for hydrolyzing xylan into its constituent sugars for subsequent fermentation to biofuels. Therefore, microorganisms are considered an important source of biocatalysts in the emerging biofuel industry. To produce an optimized enzymatic cocktail for xylan deconstruction, it will be valuable to gain insight at the molecular level of the chemical linkages and the mechanisms by which these enzymes recognize their substrates and catalyze their reactions. Recent advances in genomics, proteomics, and structural biology have revolutionized our understanding of the microbial xylanolytic enzymes. This review focuses on current understanding of the molecular basis for substrate specificity and catalysis by enzymes involved in xylan deconstruction. PMID:20431716

Dodd, Dylan; Cann, Isaac K O

2009-02-18

37

The potential of C4 grasses for cellulosic biofuel production  

PubMed Central

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.

van der Weijde, Tim; Alvim Kamei, Claire L.; Torres, Andres F.; Vermerris, Wilfred; Dolstra, Oene; Visser, Richard G. F.; Trindade, Luisa M.

2013-01-01

38

The potential of C4 grasses for cellulosic biofuel production.  

PubMed

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. PMID:23653628

van der Weijde, Tim; Alvim Kamei, Claire L; Torres, Andres F; Vermerris, Wilfred; Dolstra, Oene; Visser, Richard G F; Trindade, Luisa M

2013-01-01

39

Production of liquid biofuels from renewable resources  

Microsoft Academic Search

This article is an up-to-date review of the literature available on the subject of liquid biofuels. In search of a suitable fuel alternative to fast depleting fossil fuel and oil reserves and in serious consideration of the environmental issues associated with the extensive use of fuels based on petrochemicals, research work is in progress worldwide. Researchers have been re-directing their

Poonam Singh Nigam; Anoop Singh

2011-01-01

40

World Biofuels Production Potential Understanding the Challenges to Meeting the U.S. Renewable Fuel Standard  

Microsoft Academic Search

This study by the U.S. Department of Energy (DOE) estimates the worldwide potential to produce biofuels including biofuels for export. It was undertaken to improve our understanding of the potential for imported biofuels to satisfy the requirements of Title II of the 2007 Energy Independence and Security Act (EISA) in the coming decades. Many other countries biofuels production and policies

B. Sastri; A. Lee

2008-01-01

41

Limits to biofuels  

NASA Astrophysics Data System (ADS)

Biofuel production is dependent upon agriculture and forestry systems, and the expectations of future biofuel potential are high. A study of the global food production and biofuel production from edible crops implies that biofuel produced from edible parts of crops lead to a global deficit of food. This is rather well known, which is why there is a strong urge to develop biofuel systems that make use of residues or products from forest to eliminate competition with food production. However, biofuel from agro-residues still depend upon the crop production system, and there are many parameters to deal with in order to investigate the sustainability of biofuel production. There is a theoretical limit to how much biofuel can be achieved globally from agro-residues and this amounts to approximately one third of todays' use of fossil fuels in the transport sector. In reality this theoretical potential may be eliminated by the energy use in the biomass-conversion technologies and production systems, depending on what type of assessment method is used. By surveying existing studies on biofuel conversion the theoretical limit of biofuels from 2010 years' agricultural production was found to be either non-existent due to energy consumption in the conversion process, or up to 2-6000TWh (biogas from residues and waste and ethanol from woody biomass) in the more optimistic cases.

Johansson, S.

2013-06-01

42

Biofuels  

NSDL National Science Digital Library

In this lesson, learners will design a fermentation experiment and use their data as well as outside research to design a biorefinery plant. Learners design an experiment to compare the amount of ethanol produced by the fermentation of materials such as corn, grass and fruits. Learners research the pros and cons of growing and processing these materials for use as biofuels. Learners also design a biorefinery plant.

Boulder, University O.

2012-01-01

43

Germany: Bio-Fuels. Read-Out from Fuels of the Future Congress in Berlin, 2008. GAIN Report Number GM8051.  

National Technical Information Service (NTIS)

The hot topics of the 6th Fuels of the Future Congress in Berlin included the proposed changes in the German biofuels laws, sustainability criteria for biofuels, and the food versus fuel debate. German biofuels organizations criticized the proposed reduct...

S. Lieberz

2008-01-01

44

Projecting future grassland performance in the Greater Platte River Basin to assess sustainability for potential biofuel feedstock areas  

NASA Astrophysics Data System (ADS)

In previous studies, we used vegetation condition information from archival records of satellite data (i.e., 10-year time series of Normalized Difference Vegetation Index (NDVI) data), site geophysical and biophysical features (e.g., elevation, slope and aspect, and soils), and weather and climate drivers to build ecosystem performance (EP) models to dynamically monitor EP (DMEP) in the Greater Platte River Basin (GPRB). Ecosystem performance is a surrogate approach for measuring ecosystem productivity. We estimated ecosystem site potentials (i.e., long-term ecosystem productivities), weather-based expected EP (EEP), and rangeland conditions based on these EP models. Validation of the EP results using ground observations (e.g., percentage of bare soil, LANDFIRE maps, stocking rate, and crop yield data) demonstrated the reliability of these EP models. We used this DMEP method to identify grasslands that are potentially suitable for cellulosic biofuel feedstock (e.g., switchgrass) development in the GPRB. The objectives of this study are to (1) project the future grassland EP; (2) assess the changes and trends of the future EP; and (3) examine the future sustainability of the identified biofuel feedstock areas in the GPRB. We used the EP models and future climate projections to estimate future (e.g., 2050 and 2099) climate-based projections of grassland performance in the GPRB. The future climate data were derived from the National Center for Atmospheric Research (NCAR) Community Climate System Model 3.0 (CCSM3) "SRES A1B" (a "middle" emissions path) obtained from the "Bias Corrected and Downscaled WCRP CMIP3 Climate Projections" archive (http://gdo-dcp.ucllnl.org/downscaled_cmip3_projections). Results show that, under climate scenario A1B, the potential biofuel feedstock areas in the more mesic Eastern part of the GPRB will remain productive in the future (the spatially averaged EPs for these areas are 3335 kg ha-1 year-1, 3355 kg ha-1 year-1, and 3341 kg ha-1 year-1 for the site potential, the 2050 EEP, and the 2099 EEP, respectively). Therefore, the identified potential biofuel feedstock areas will continue to be sustainable for future biofuel development. On the other hand, the identified non-biofuel grasslands in the drier Western part of the GPRB would be expected to stay unproductive, with a slight decline in the EP trend in the future (spatially averaged EPs are 1983 kg ha-1 year-1, 1977 kg ha-1 year-1, and 1964 kg ha-1 year-1 for the site potential, the 2050 EEP, and the 2099 EEP, respectively). Thus, these areas will continue to be unsuitable for biofuel feedstock development in the future. The resulting future grassland EEP maps can be used as a reference by land managers to assess the future sustainability and feasibility of the potential biofuel feedstock areas.

Gu, Y.; Wylie, B. K.; Phuyal, K.

2012-12-01

45

Addressing the challenges for sustainable production of algal biofuels: II. Harvesting and conversion to biofuels.  

PubMed

In order to ensure the sustainability of algal biofuel production, a number of issues need to be addressed. Previously, we reviewed some of the questions in this area involving algal species and the important challenges of nutrient supply and how these might be met. Here, we take up issues involving harvesting and the conversion ofbiomass to biofuels. Advances in both these areas are required if these third-generation fuels are to have a sufficiently high net energy ratio and a sustainable footprint. A variety of harvesting technologies are under investigation and recent studies in this area are presented and discussed. A number of different energy uses are available for algal biomass, each with their own advantages as well as challenges in terms of efficiencies and yields. Recent advances in these areas are presented and some of the especially promising conversion processes are highlighted. PMID:24350436

Abdelaziz, Ahmed E M; Leite, Gustavo B; Hallenbeck, Patrick C

2013-01-01

46

Biofuel production by in vitro synthetic enzymatic pathway biotransformation.  

PubMed

Cell-free synthetic pathway biotransformation (SyPaB) is the implementation of complicated biochemical reactions by in vitro assembling a number of enzymes or their complexes and coenzymes. Assembly of numerous enzymes without cellular membrane, gene regulation, or undesired pathway can circumvent some of the obstacles to modifying living microorganisms. Several synthetic pathways for the production of liquid biofuels--alcohols and hydrocarbon precursors (polyols) as well as gaseous biofuel--hydrogen have been presented. The present constraints to SyPaB include the lack of stable enzymes as Lego-like building blocks, the different optimal reaction conditions for individual enzyme, and the use of costly labile coenzymes. It is expected that high-yield SyPaB will be an important platform for producing low-cost biofuels and biochemicals. PMID:20566280

Zhang, Y-H Percival; Sun, Jibin; Zhong, Jian-Jiang

2010-10-01

47

Biofuels production for smallholder producers in the Greater Mekong Subregion  

Microsoft Academic Search

Looming concerns on rising food prices and food security has slowed down the impetus in biofuel production. The development of the sub-sector, however, remains an important agenda among developing countries like those of the Greater Mekong Sub-region (GMS) that have abundant labour and natural resources but have limited supply of fossil fuels which continues to serve as a constraint to

Urooj S. Malik; Mahfuz Ahmed; Mercedita A. Sombilla; Sarah L. Cueno

2009-01-01

48

Sustainability of Biofuels Workshop. State of the Science and Future Directions, October 28-29, 2008.  

National Technical Information Service (NTIS)

Legislative mandates and incentives, volatility in oil prices, and new research and technological advances are driving the expectation of major increases in the production of biofuels from cellulosic biomass. To assess the current state of the science und...

2008-01-01

49

Biological pretreatment for production of lignocellulosic biofuel.  

PubMed

Lignocellulosic biomass was submitted to a biological pretreatment prior to a catalytic hydroliquefaction in order to produce biofuel. The biodegradation process was conducted over 3 months in a reactor under controlled conditions. During the biodegradation process the organic matter was characterised and its evolution was correlated with physico-chemical parameters. In parallel with the analysis of the lipidic fraction, analytical pyrolysis was used to monitor bacterial activity. The alterations of branched to linear fatty acids ratio and of mono- to diacids ratio were compared when determined by thermochemolysis and observed in the directly extractable lipids. The evolution of the phytol to the corresponding isoprenoic ketone ratio was observed to be dependent on the desorption technique since it decreases using headspace while it increases using pyrolysis. "Humic"/"fulvic acids" ratio, infrared spectroscopy and thermodifferential analysis were used to determine the degree of OM complexification. PMID:22617032

Lemée, L; Kpogbemabou, D; Pinard, L; Beauchet, R; Laduranty, J

2012-08-01

50

Wastewater treatment high rate algal ponds for biofuel production.  

PubMed

While research and development of algal biofuels are currently receiving much interest and funding, they are still not commercially viable at today's fossil fuel prices. However, a niche opportunity may exist where algae are grown as a by-product of high rate algal ponds (HRAPs) operated for wastewater treatment. In addition to significantly better economics, algal biofuel production from wastewater treatment HRAPs has a much smaller environmental footprint compared to commercial algal production HRAPs which consume freshwater and fertilisers. In this paper the critical parameters that limit algal cultivation, production and harvest are reviewed and practical options that may enhance the net harvestable algal production from wastewater treatment HRAPs including CO(2) addition, species control, control of grazers and parasites and bioflocculation are discussed. PMID:20674341

Park, J B K; Craggs, R J; Shilton, A N

2011-01-01

51

The Role of Synthetic Biology in the Design of Microbial Cell Factories for Biofuel Production  

PubMed Central

Insecurity in the supply of fossil fuels, volatile fuel prices, and major concerns regarding climate change have sparked renewed interest in the production of fuels from renewable resources. Because of this, the use of biodiesel has grown dramatically during the last few years and is expected to increase even further in the future. Biodiesel production through the use of microbial systems has marked a turning point in the field of biofuels since it is emerging as an attractive alternative to conventional technology. Recent progress in synthetic biology has accelerated the ability to analyze, construct, and/or redesign microbial metabolic pathways with unprecedented precision, in order to permit biofuel production that is amenable to industrial applications. The review presented here focuses specifically on the role of synthetic biology in the design of microbial cell factories for efficient production of biodiesel.

Colin, Veronica Leticia; Rodriguez, Analia; Cristobal, Hector Antonio

2011-01-01

52

Synthetic Feedback Loop Model for Increasing Microbial Biofuel Production Using a Biosensor  

PubMed Central

Current biofuel production methods use engineered bacteria to break down cellulose and convert it to biofuel. A major challenge in microbial fuel production is that increasing biofuel yields can be limited by the toxicity of the biofuel to the organism that is producing it. Previous research has demonstrated that efflux pumps are effective at increasing tolerance to various biofuels. However, when overexpressed, efflux pumps burden cells, which hinders growth and slows biofuel production. Therefore, the toxicity of the biofuel must be balanced with the toxicity of pump overexpression. We have developed a mathematical model for cell growth and biofuel production that implements a synthetic feedback loop using a biosensor to control efflux pump expression. In this way, the production rate will be maximal when the concentration of biofuel is low because the cell does not expend energy expressing efflux pumps when they are not needed. Additionally, the microbe is able to adapt to toxic conditions by triggering the expression of efflux pumps, which allow it to continue biofuel production. Sensitivity analysis indicates that the feedback sensor model is insensitive to many system parameters, but a few key parameters can influence growth and production. In comparison to systems that express efflux pumps at a constant level, the feedback sensor increases overall biofuel production by delaying pump expression until it is needed. This result is more pronounced when model parameters are variable because the system can use feedback to adjust to the actual rate of biofuel production.

Harrison, Mary E.; Dunlop, Mary J.

2012-01-01

53

Spatially explicit modelling of biofuel crops in Europe  

Microsoft Academic Search

This paper describes a methodology to explore the (future) spatial distribution of biofuel crops in Europe. Two main types of biofuel crops are distinguished: biofuel crops used for the production of biodiesel or bioethanol, and second-generation biofuel crops. A multi-scale, multi-model approach is used in which biofuel crops are allocated over the period 2000–2030. The area of biofuel crops at

Fritz Hellmann; Peter H. Verburg

2011-01-01

54

Exergy efficiency analysis of chemical and biochemical stages involved in liquid biofuels production processes  

Microsoft Academic Search

Liquid biofuels can be produced from a variety of feedstocks and processes. Ethanol and biodiesel production processes based on conventional raw materials are already commercial, but subject to further improvement and optimization. Biofuels production processes using lignocellulosic feedstocks are still in the demonstration phase and require further R&D to increase efficiency. A primary tool to analyze the efficiency of biofuels

H. I. Velásquez-Arredondo; S. De Oliveira Junior; P. Benjumea

55

Microalgae as a raw material for biofuels production.  

PubMed

Biofuels demand is unquestionable in order to reduce gaseous emissions (fossil CO(2), nitrogen and sulfur oxides) and their purported greenhouse, climatic changes and global warming effects, to face the frequent oil supply crises, as a way to help non-fossil fuel producer countries to reduce energy dependence, contributing to security of supply, promoting environmental sustainability and meeting the EU target of at least of 10% biofuels in the transport sector by 2020. Biodiesel is usually produced from oleaginous crops, such as rapeseed, soybean, sunflower and palm. However, the use of microalgae can be a suitable alternative feedstock for next generation biofuels because certain species contain high amounts of oil, which could be extracted, processed and refined into transportation fuels, using currently available technology; they have fast growth rate, permit the use of non-arable land and non-potable water, use far less water and do not displace food crops cultures; their production is not seasonal and they can be harvested daily. The screening of microalgae (Chlorella vulgaris, Spirulina maxima, Nannochloropsis sp., Neochloris oleabundans, Scenedesmus obliquus and Dunaliella tertiolecta) was done in order to choose the best one(s), in terms of quantity and quality as oil source for biofuel production. Neochloris oleabundans (fresh water microalga) and Nannochloropsis sp. (marine microalga) proved to be suitable as raw materials for biofuel production, due to their high oil content (29.0 and 28.7%, respectively). Both microalgae, when grown under nitrogen shortage, show a great increase (approximately 50%) in oil quantity. If the purpose is to produce biodiesel only from one species, Scenedesmus obliquus presents the most adequate fatty acid profile, namely in terms of linolenic and other polyunsaturated fatty acids. However, the microalgae Neochloris oleabundans, Nannochloropsis sp. and Dunaliella tertiolecta can also be used if associated with other microalgal oils and/or vegetable oils. PMID:18982369

Gouveia, Luisa; Oliveira, Ana Cristina

2009-02-01

56

Cultivation and Characterization of Cynara Cardunculus for Solid Biofuels Production in the Mediterranean Region  

PubMed Central

Technical specifications of solid biofuels are continuously improved towards the development and promotion of their market. Efforts in the Greek market are limited, mainly due to the climate particularity of the region, which hinders the growth of suitable biofuels. Taking also into account the increased oil prices and the high inputs required to grow most annual crops in Greece, cardoon (Cynara cardunculus L.) is now considered the most important and promising sources for solid biofuel production in Greece in the immediate future. The reason is that cardoon is a perennial crop of Mediterranean origin, well adapted to the xerothermic conditions of southern Europe, which can be utilized particularly for solid biofuel production. This is due to its minimum production cost, as this perennial weed may perform high biomass productivity on most soils with modest or without any inputs of irrigation and agrochemicals. Within this framework, the present research work is focused on the planning and analysis of different land use scenarios involving this specific energy crop and the combustion behaviour characterization for the solid products. Such land use scenarios are based on quantitative estimates of the crop'sproduction potential under specific soil-climatic conditions as well as the inputs required for its realization in comparison to existing conventional crops. Concerning its decomposition behaviour, devolatilisation and char combustion tests were performed in a non-isothermal thermogravimetric analyser (TA Q600). A kinetic analysis was applied and accrued results were compared with data already available for other lignocellulosic materials. The thermogravimetric analysis showed that the decomposition process of cardoon follows the degradation of other lignocellulosic fuels, meeting high burnout rates. This research work concludes that Cynara cardunculus, under certain circumstances, can be used as a solid biofuel of acceptable quality.

Grammelis, Panagiotis; Malliopoulou, Anastasia; Basinas, Panagiotis; Danalatos, Nicholas G.

2008-01-01

57

Sequencing of multiple clostridial genomes related to biomass conversion and biofuel production.  

PubMed

Modern methods to develop microbe-based biomass conversion processes require a system-level understanding of the microbes involved. Clostridium species have long been recognized as ideal candidates for processes involving biomass conversion and production of various biofuels and other industrial products. To expand the knowledge base for clostridial species relevant to current biofuel production efforts, we have sequenced the genomes of 20 species spanning multiple genera. The majority of species sequenced fall within the class III cellulosome-encoding Clostridium and the class V saccharolytic Thermoanaerobacteraceae. Species were chosen based on representation in the experimental literature as model organisms, ability to degrade cellulosic biomass either by free enzymes or by cellulosomes, ability to rapidly ferment hexose and pentose sugars to ethanol, and ability to ferment synthesis gas to ethanol. The sequenced strains significantly increase the number of noncommensal/nonpathogenic clostridial species and provide a key foundation for future studies of biomass conversion, cellulosome composition, and clostridial systems biology. PMID:20889752

Hemme, Christopher L; Mouttaki, Housna; Lee, Yong-Jin; Zhang, Gengxin; Goodwin, Lynne; Lucas, Susan; Copeland, Alex; Lapidus, Alla; Glavina del Rio, Tijana; Tice, Hope; Saunders, Elizabeth; Brettin, Thomas; Detter, John C; Han, Cliff S; Pitluck, Sam; Land, Miriam L; Hauser, Loren J; Kyrpides, Nikos; Mikhailova, Natalia; He, Zhili; Wu, Liyou; Van Nostrand, Joy D; Henrissat, Bernard; He, Qiang; Lawson, Paul A; Tanner, Ralph S; Lynd, Lee R; Wiegel, Juergen; Fields, Matthew W; Arkin, Adam P; Schadt, Christopher W; Stevenson, Bradley S; McInerney, Michael J; Yang, Yunfeng; Dong, Hailiang; Xing, Defeng; Ren, Nanqi; Wang, Aijie; Huhnke, Raymond L; Mielenz, Jonathan R; Ding, Shi-You; Himmel, Michael E; Taghavi, Safiyh; van der Lelie, Daniël; Rubin, Edward M; Zhou, Jizhong

2010-12-01

58

Sequencing of Multiple Clostridial Genomes Related to Biomass Conversion and Biofuel Production  

SciTech Connect

Modern methods to develop microbe-based biomass conversion processes require a system-level understanding of the microbes involved. Clostridium species have long been recognized as ideal candidates for processes involving biomass conversion and production of various biofuels and other industrial products. To expand the knowledge base for clostridial species relevant to current biofuel production efforts, we have sequenced the genomes of 20 species spanning multiple genera. The majority of species sequenced fall within the class III cellulosome-encoding Clostridium and the class V saccharolytic Thermoanaerobacteraceae. Species were chosen based on representation in the experimental literature as model organisms, ability to degrade cellulosic biomass either by free enzymes or by cellulosomes, ability to rapidly ferment hexose and pentose sugars to ethanol, and ability to ferment synthesis gas to ethanol. The sequenced strains significantly increase the number of noncommensal/nonpathogenic clostridial species and provide a key foundation for future studies of biomass conversion, cellulosome composition, and clostridial systems biology.

Hemme, Christopher [University of Oklahoma; Mouttaki, Housna [University of Oklahoma; Lee, Yong-Jin [University of Oklahoma, Norman; Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Copeland, A [U.S. Department of Energy, Joint Genome Institute; Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Glavina Del Rio, Tijana [U.S. Department of Energy, Joint Genome Institute; Tice, Hope [U.S. Department of Energy, Joint Genome Institute; Saunders, Elizabeth H [Los Alamos National Laboratory (LANL); Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Han, Cliff [Los Alamos National Laboratory (LANL); Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Mikhailova, Natalia [U.S. Department of Energy, Joint Genome Institute; He, Zhili [University of Oklahoma; Wu, Liyou [University of Oklahoma, Norman; Van Nostrand, Joy [University of Oklahoma, Norman; Henrissat, Bernard [Universite d'Aix-Marseille I & II; HE, Qiang [ORNL; Lawson, Paul A. [University of Oklahoma, Norman; Tanner, Ralph S. [University of Oklahoma, Norman; Lynd, Lee R [Thayer School of Engineering at Dartmouth; Wiegel, Juergen [University of Georgia, Athens, GA; Fields, Dr. Matthew Wayne [Montana State University; Arkin, Adam [Lawrence Berkeley National Laboratory (LBNL); Schadt, Christopher Warren [ORNL; Stevenson, Bradley S. [University of Oklahoma, Norman; McInerney, Michael J. [University of Oklahoma, Norman; Yang, Yunfeng [ORNL; Dong, Hailiang [Miami University, Oxford, OH; Xing, Defeng [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology; Ren, Nanqi [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology; Wang, Aijie [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology; Ding, Shi-You [National Energy Renewable Laboratory; Himmel, Michael E [National Renewable Energy Laboratory (NREL); Taghavi, Safiyh [Brookhaven National Laboratory (BNL)/U.S. Department of Energy; Van Der Lelie, Daniel [Brookhaven National Laboratory (BNL); Rubin, Edward M. [U.S. Department of Energy, Joint Genome Institute; Zhou, Jizhong [University of Oklahoma

2010-01-01

59

Production of biofuels from synthesis gas using microbial catalysts.  

PubMed

World energy consumption is expected to increase 44% in the next 20 years. Today, the main sources of energy are oil, coal, and natural gas, all fossil fuels. These fuels are unsustainable and contribute to environmental pollution. Biofuels are a promising source of sustainable energy. Feedstocks for biofuels used today such as grain starch are expensive and compete with food markets. Lignocellulosic biomass is abundant and readily available from a variety of sources, for example, energy crops and agricultural/industrial waste. Conversion of these materials to biofuels by microorganisms through direct hydrolysis and fermentation can be challenging. Alternatively, biomass can be converted to synthesis gas through gasification and transformed to fuels using chemical catalysts. Chemical conversion of synthesis gas components can be expensive and highly susceptible to catalyst poisoning, limiting biofuel yields. However, there are microorganisms that can convert the CO, H(2), and CO(2) in synthesis gas to fuels such as ethanol, butanol, and hydrogen. Biomass gasification-biosynthesis processing systems have shown promise as some companies have already been exploiting capable organisms for commercial purposes. The discovery of novel organisms capable of higher product yield, as well as metabolic engineering of existing microbial catalysts, makes this technology a viable option for reducing our dependency on fossil fuels. PMID:20359454

Tirado-Acevedo, Oscar; Chinn, Mari S; Grunden, Amy M

2010-01-01

60

Piedmont Biofuels Homepage  

NSDL National Science Digital Library

The Piedmont Biofuels homepage provides access to information about small industrial production of biodiesel, biofuels educational programs at Cental Carolina Community College, and volunteer opportunities in biofuels.

2006-10-31

61

Multiphase Flow Modeling of Biofuel Production Processes  

Microsoft Academic Search

As part of the Idaho National Laboratory's (INL's) Secure Energy Initiative, the INL is performing research in areas that are vital to ensuring clean, secure energy supplies for the future. The INL Hybrid Energy Systems Testing (HYTEST) Laboratory is being established to develop and test hybrid energy systems with the principal objective to safeguard U.S. Energy Security by reducing dependence

D. Gaston; D. P. Guillen; J. Tester

2011-01-01

62

Comparative cost analysis of algal oil production for biofuels  

Microsoft Academic Search

Economic analysis is an essential evaluation for considering feasibility and viability of large-scale, photoautotrophic algae-based, biofuel production. Thus far, economic analysis has been conducted on a scenario-by-scenario basis which does not allow for cross-comparisons. In 2008, a comparative study was carried out using a cross-section of cost analyses consisting of 12 public studies. The resulting triacylglyceride cost had a spread

Amy Sun; Ryan Davis; Meghan Starbuck; Ami Ben-Amotz; Ron Pate; Philip T. Pienkos

2011-01-01

63

The US Ethanol and Biofuels Boom: Its Origins, Current Status, and Future Prospects  

NSDL National Science Digital Library

This article explains why we are experiencing a boom in ethanol and other biofuels, the current status of biofuels, and prospects for the future under different policy regimes. I argue that today's boom is in a sense an unintended consequence of a fixed ethanol subsidy that was keyed to $20-per-barrel crude oil, combined with a surge in crude oil pricesinitially to $60 per barrel, and later doubling to $120 per barrel. Future prospects for corn ethanol depend on the crude oil price, the price of corn and distillers' grains, the market value of ethanol, plant capital and operating costs, and federal ethanol and biofuels policies. I examine the impacts of a wide range of policies for subsidies and renewable fuels standards. Policy choices will be absolutely critical in determining the extent to which biofuels targets are achieved and at what cost. However, if the price of oil remains above $100 per barrel, biofuels will continue to be produced even without government interventions.

Wallace E. Tyner (Purdue University;)

2008-08-01

64

Fatty acid alkyl esters: perspectives for production of alternative biofuels.  

PubMed

The global economy heads for a severe energy crisis: whereas the energy demand is going to rise, easily accessible sources of crude oil are expected to be depleted in only 10-20 years. Since a serious decline of oil supply and an associated collapse of the economy might be reality very soon, alternative energies and also biofuels that replace fossil fuels must be established. In addition, these alternatives should not further impair the environment and climate. About 90% of the biofuel market is currently captured by bioethanol and biodiesel. Biodiesel is composed of fatty acid alkyl esters (FAAE) and can be synthesized by chemical, enzymatic, or in vivo catalysis mainly from renewable resources. Biodiesel is already established as it is compatible with the existing fuel infrastructure, non-toxic, and has superior combustion characteristics than fossil diesel; and in 2008, the global production was 12.2 million tons. The biotechnological production of FAAE from low cost and abundant feedstocks like biomass will enable an appreciable substitution of petroleum diesel. To overcome high costs for immobilized enzymes, the in vivo synthesis of FAAE using bacteria represents a promising approach. This article points to the potential of different FAAE as alternative biofuels, e.g., by comparing their fuel properties. In addition to conventional production processes, this review presents natural and genetically engineered biological systems capable of in vivo FAAE synthesis. PMID:20033403

Röttig, Annika; Wenning, Leonie; Bröker, Daniel; Steinbüchel, Alexander

2010-02-01

65

BIOFUEL AND BIOENERGY PRODUCTION FROM SUGAR BEETS  

EPA Science Inventory

A design spreadsheet model for sizing and analyzing the integrated ethanol and biogas production system, a prototype of the ethanol and biogas production system in the laboratory that has been tested and documented with performance data, and a design and operating manual for t...

66

Biofuel Production in Italy and Europe: Benefits and Costs, in the Light of the Present European Union Biofuel Policy  

Microsoft Academic Search

We present and critically evaluate in this paper biofuel production options in Italy, in order to provide the reader with\\u000a the order of magnitudes of the performance indicators involved. Also, we discuss biofuel viability and desirability at the\\u000a European level, according to the recent EU regulations and energy policy decisions.\\u000a \\u000a Fuels from biomass are most often proposed as substitutes for

Sergio Ulgiati; Daniela Russi; Marco Raugei

67

Microalgal Triacylglycerols as Feedstocks for Biofuel Production: Perspectives and Advances  

SciTech Connect

Microalgae represent an exceptionally diverse but highly specialized group of micro-organisms adapted to various ecological habitats. Many microalgae have the ability to produce substantial amounts (e.g. 20-50% dry cell weight) of triacylglycerols (TAG) as a storage lipid under photo-oxidative stress or other adverse environmental conditions. Fatty acids, the building blocks for TAGs and all other cellular lipids, are synthesized in the chloroplast using a single set of enzymes, of which acetyl CoA carboxylase (ACCase) is key in regulating fatty acid synthesis rates. However, the expression of genes involved in fatty acid synthesis is poorly understood in microalgae. Synthesis and sequestration of TAG into cytosolic lipid bodies appear to be a protective mechanism by which algal cells cope with stress conditions, but little is known about regulation of TAG formation at the molecular and cellular level. While the concept of using microalgae as an alternative and renewable source of lipid-rich biomass feedstock for biofuels has been explored over the past few decades, a scalable, commercially viable system has yet to emerge. Today, the production of algal oil is primarily confined to high-value specialty oils with nutritional value, rather than commodity oils for biofuel. This review provides a brief summary of the current knowledge on oleaginous algae and their fatty acid and TAG biosynthesis, algal model systems and genomic approaches to a better understanding of TAG production, and a historical perspective and path forward for microalgae-based biofuel research and commercialization.

Hu, Q.; Sommerfeld, M.; Jarvis, E.; Ghirardi, M.; Posewitz, M; Seibert, M.; Darzins, A.

2008-01-01

68

National Microalgae Biofuel Production Potential and Resource Demand  

SciTech Connect

Microalgae continue to receive global attention as a potential sustainable "energy crop" for biofuel production. An important step to realizing the potential of algae is quantifying the demands commercial-scale algal biofuel production will place on water and land resources. We present a high-resolution national resource and oil production assessment that brings to bear fundamental research questions of where open pond microalgae production can occur, how much land and water resource is required, and how much energy is produced. Our study suggests under current technology microalgae have the potential to generate 220 billion liters/year of oil, equivalent to 48% of current U.S. petroleum imports for transportation fuels. However, this level of production would require 5.5% of the land area in the conterminous U.S., and nearly three times the volume of water currently used for irrigated agriculture, averaging 1,421 L water per L of oil. Optimizing the selection of locations for microalgae production based on water use efficiency can greatly reduce total water demand. For example, focusing on locations along the Gulf Coast, Southeastern Seaboard, and areas adjacent to the Great Lakes, shows a 75% reduction in water demand to 350 L per L of oil produced with a 67% reduction in land use. These optimized locations have the potential to generate an oil volume equivalent to 17% of imports for transportation fuels, equal to the Energy Independence and Security Act year 2022 "advanced biofuels" production target, and utilizing some 25% of the current irrigation consumptive water demand for the U. S. These results suggest that, with proper planning, adequate land and water are available to meet a significant portion of the U.S. renewable fuel goals.

Wigmosta, Mark S.; Coleman, Andre M.; Skaggs, Richard; Huesemann, Michael H.; Lane, Leonard J.

2011-04-14

69

National microalgae biofuel production potential and resource demand  

NASA Astrophysics Data System (ADS)

Microalgae are receiving increased global attention as a potential sustainable "energy crop" for biofuel production. An important step to realizing the potential of algae is quantifying the demands commercial-scale algal biofuel production will place on water and land resources. We present a high-resolution spatiotemporal assessment that brings to bear fundamental questions of where production can occur, how many land and water resources are required, and how much energy is produced. Our study suggests that under current technology, microalgae have the potential to generate 220 × 109 L yr-1 of oil, equivalent to 48% of current U.S. petroleum imports for transportation. However, this level of production requires 5.5% of the land area in the conterminous United States and nearly three times the water currently used for irrigated agriculture, averaging 1421 L water per liter of oil. Optimizing the locations for microalgae production on the basis of water use efficiency can greatly reduce total water demand. For example, focusing on locations along the Gulf Coast, southeastern seaboard, and Great Lakes shows a 75% reduction in consumptive freshwater use to 350 L per liter of oil produced with a 67% reduction in land use. These optimized locations have the potential to generate an oil volume equivalent to 17% of imports for transportation fuels, equal to the Energy Independence and Security Act year 2022 "advanced biofuels" production target and utilizing some 25% of the current irrigation demand. With proper planning, adequate land and water are available to meet a significant portion of the U.S. renewable fuel goals.

Wigmosta, Mark S.; Coleman, André M.; Skaggs, Richard J.; Huesemann, Michael H.; Lane, Leonard J.

2011-03-01

70

A model for improving microbial biofuel production using a synthetic feedback loop  

PubMed Central

Cells use feedback to implement a diverse range of regulatory functions. Building synthetic feedback control systems may yield insight into the roles that feedback can play in regulation since it can be introduced independently of native regulation, and alternative control architectures can be compared. We propose a model for microbial biofuel production where a synthetic control system is used to increase cell viability and biofuel yields. Although microbes can be engineered to produce biofuels, the fuels are often toxic to cell growth, creating a negative feedback loop that limits biofuel production. These toxic effects may be mitigated by expressing efflux pumps that export biofuel from the cell. We developed a model for cell growth and biofuel production and used it to compare several genetic control strategies for their ability to improve biofuel yields. We show that controlling efflux pump expression directly with a biofuel-responsive promoter is a straightforward way of improving biofuel production. In addition, a feed forward loop controller is shown to be versatile at dealing with uncertainty in biofuel production rates.

Dunlop, Mary J.; Keasling, Jay D.

2010-01-01

71

Microwave-assisted pyrolysis of biomass for liquid biofuels production.  

PubMed

Production of 2nd-generation biofuels from biomass residues and waste feedstock is gaining great concerns worldwide. Pyrolysis, a thermochemical conversion process involving rapid heating of feedstock under oxygen-absent condition to moderate temperature and rapid quenching of intermediate products, is an attractive way for bio-oil production. Various efforts have been made to improve pyrolysis process towards higher yield and quality of liquid biofuels and better energy efficiency. Microwave-assisted pyrolysis is one of the promising attempts, mainly due to efficient heating of feedstock by "microwave dielectric heating" effects. This paper presents a state-of-the-art review of microwave-assisted pyrolysis of biomass. First, conventional fast pyrolysis and microwave dielectric heating is briefly introduced. Then microwave-assisted pyrolysis process is thoroughly discussed stepwise from biomass pretreatment to bio-oil collection. The existing efforts are summarized in a table, providing a handy overview of the activities (e.g., feedstock and pretreatment, reactor/pyrolysis conditions) and findings (e.g., pyrolysis products) of various investigations. PMID:22771019

Yin, Chungen

2012-09-01

72

Production of advanced biofuels in engineered E. coli.  

PubMed

Commercial fermentation processes have long taken advantage of the synthetic power of living systems to rapidly and efficiently transform simple carbon sources into complex molecules. In this regard, the ability of yeasts to produce ethanol from glucose at exceptionally high yields has served as a key feature in its use as a fuel, but is also limited by the poor molecular properties of ethanol as a fuel such as high water miscibility and low energy density. Advances in metabolic engineering and synthetic biology allow us to begin constructing new high-flux pathways for production of next generation biofuels that are key to building a sustainable pipeline for liquid transportation fuels. PMID:23659832

Wen, Miao; Bond-Watts, Brooks B; Chang, Michelle C Y

2013-06-01

73

Systems biology of yeast: enabling technology for development of cell factories for production of advanced biofuels.  

PubMed

Transportation fuels will gradually shift from oil based fuels towards alternative fuel resources like biofuels. Current bioethanol and biodiesel can, however, not cover the increasing demand for biofuels and there is therefore a need for advanced biofuels with superior fuel properties. Novel cell factories will provide a production platform for advanced biofuels. However, deep cellular understanding is required for improvement of current biofuel cell factories. Fast screening and analysis (-omics) methods and metabolome-wide mathematical models are promising techniques. An integrated systems approach of these techniques drives diversity and quantity of several new biofuel compounds. This review will cover the recent technological developments that support improvement of the advanced biofuels 1-butanol, biodiesels and jetfuels. PMID:22169890

de Jong, Bouke; Siewers, Verena; Nielsen, Jens

2012-08-01

74

Production and harvesting of microalgae for wastewater treatment, biofuels, and bioproducts  

Microsoft Academic Search

The integration of microalgae-based biofuel and bioproducts production with wastewater treatment has major advantages for both industries. However, major challenges to the implementation of an integrated system include the large-scale production of algae and the harvesting of microalgae in a way that allows for downstream processing to produce biofuels and other bioproducts of value. Although the majority of algal production

Logan Christenson; Ronald Sims

2011-01-01

75

Fields of dreams: Agriculture, economy and nature in Midwest United States biofuel production  

NASA Astrophysics Data System (ADS)

This work explores the social and ecological dimensions of recent biofuel production increases in the United States (US), focusing on the case of Iowa. Biofuels are proposed to mitigate the greenhouse gas emissions that cause climate change, improve US energy security, and support rural economies. Little research has examined how increased US Midwestern biofuels production will change social and ecological outcomes at farm and regional levels or interact with broader governance processes at the nexus of agriculture, energy and environment. These broad questions guide my research: (1) How does biofuel production reconfigure agricultural practice and landscapes in Iowa? (2) What are the costs, benefits and risks of increased biofuels production as seen by farmers and rural residents, and how do these factors influence farmer decisions about agriculture and conservation practice? (3) How and with what effects are biofuels initiatives constituted as a form of environmental governance through scientific knowledge and practice and political economic dynamics? To address these questions, this research integrates both qualitative and quantitative methods, drawing on a political ecological approach complemented by agroecological analysis and theoretical insights from geographical analyses of nature-society relations. Quantitative analysis focuses on changing land use patterns in agriculture and conservation practice in Iowa. Qualitative methods include extensive interviews, participant observation, and policy and document analyses. Fieldwork focused on Northeastern Iowa to understand regional changes in agricultural and conservation practice, the renegotiated position of farmers in agriculture and biofuel production, and biofuel industry development. I find that biofuel production presents significant social and ecological challenges for rural places of production. Longstanding, unequal political economic relations in industrialized agriculture limit rural economic benefits. I describe how biofuel governance focuses on scientific practices that legitimize biofuel production for their capacity to marginally reduce greenhouse gas emissions, despite biofuels' agroecological consequences outside this regulatory purview. These consequences include pressure on conservation and agrienvironmental practice, which could be better supported through existing, highly effective, place-based, democratic institutions dedicated to stewarding the resources upon which agricultural livelihoods depend.

Gillon, Sean Thomas

76

Resource demand implications for US algae biofuels production scale-up  

Microsoft Academic Search

Photosynthetic microalgae with the potential for high biomass and oil productivities have long been viewed as a promising class of feedstock for biofuels to displace petroleum-based transportation fuels. Algae offer the additional benefits of potentially being produced without using high-value arable land and fresh water, thereby reducing the competition for those resources between expanding biofuels production and conventional agriculture. Algae

Ron Pate; Geoff Klise; Ben Wu

2011-01-01

77

Biofuels from Microalgae: Review of Products, Processes and Potential, with Special Focus on Dunaliella sp  

Microsoft Academic Search

There is currently great interest in using microalgae for the production of biofuels, mainly due to the fact that microalgae can produce biofuels at a much higher productivity than conventional plants and that they can be cultivated using water, in particular seawater, and land not competing for resources with conventional agriculture. However, at present such microalgae-based technologies are not yet

Michael H. Huesemann; John R. Benemann

2009-01-01

78

Your World Magazine - Biofuels: Energy for Your Future  

SciTech Connect

Policymakers have been talking for years about measures to cut back how much petroleum we use. Interest has spiked recently, with government and private companies coming together to push forward scientific research and development of alternative fuel products such as ethanol. Biotechnology is helping make alternative energy sources easier - and more affordable - to produce. Most of the world's energy needs are met with oil and natural gas, which come from fossil fuel. No one knows how long the supply can last. Biobased fuels come from natural sources that can be replaced quickly. Along with corn, there are many other grains, grasses, trees, and even agricultural wastes being investigated for their usefulness and environmental friendliness as alternative fuel sources. Careers in this emerging new field emphasize chemistry and engineering. Look into it for a potential career - it's definitely a job full of energy.

Biotechnology Institute

2006-10-01

79

Fatty acid synthesis in Escherichia coli and its applications towards the production of fatty acid based biofuels  

PubMed Central

The idea of renewable and regenerative resources has inspired research for more than a hundred years. Ideally, the only spent energy will replenish itself, like plant material, sunlight, thermal energy or wind. Biodiesel or ethanol are examples, since their production relies mainly on plant material. However, it has become apparent that crop derived biofuels will not be sufficient to satisfy future energy demands. Thus, especially in the last decade a lot of research has focused on the production of next generation biofuels. A major subject of these investigations has been the microbial fatty acid biosynthesis with the aim to produce fatty acids or derivatives for substitution of diesel. As an industrially important organism and with the best studied microbial fatty acid biosynthesis, Escherichia coli has been chosen as producer in many of these studies and several reviews have been published in the fields of E. coli fatty acid biosynthesis or biofuels. However, most reviews discuss only one of these topics in detail, despite the fact, that a profound understanding of the involved enzymes and their regulation is necessary for efficient genetic engineering of the entire pathway. The first part of this review aims at summarizing the knowledge about fatty acid biosynthesis of E. coli and its regulation, and it provides the connection towards the production of fatty acids and related biofuels. The second part gives an overview about the achievements by genetic engineering of the fatty acid biosynthesis towards the production of next generation biofuels. Finally, the actual importance and potential of fatty acid-based biofuels will be discussed.

2014-01-01

80

Carbon Calculator for Land Use Change from Biofuels Production (CCLUB). Users' Manual and Technical Documentation.  

National Technical Information Service (NTIS)

The Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) calculates carbon emissions from land use change (LUC) for four different ethanol production pathways including corn grain ethanol and cellulosic ethanol from corn stover, miscanth...

J. B. Dunn M. Wang S. Mueller

2011-01-01

81

From flavors and pharmaceuticals to advanced biofuels: production of isoprenoids in Saccharomyces cerevisiae.  

PubMed

Isoprenoids denote the largest group of chemicals in the plant kingdom and are employed for a wide range of applications in the food and pharmaceutical industry. In recent years, isoprenoids have additionally been recognized as suitable replacements for petroleum-derived fuels and could thus promote the transition towards a more sustainable society. To realize the biofuel potential of isoprenoids, a very efficient production system is required. While complex chemical structures as well as the low abundance in nature demonstrate the shortcomings of chemical synthesis and plant extraction, isoprenoids can be produced by genetically engineered microorganisms from renewable carbon sources. In this article, we summarize the development of isoprenoid applications from flavors and pharmaceuticals to advanced biofuels and review the strategies to design microbial cell factories, focusing on Saccharomyces cerevisiae for the production of these compounds. While the high complexity of biosynthetic pathways and the toxicity of certain isoprenoids still denote challenges that need to be addressed, metabolic engineering has enabled large-scale production of several terpenoids and thus, the utilization of these compounds is likely to expand in the future. PMID:24227704

Tippmann, Stefan; Chen, Yun; Siewers, Verena; Nielsen, Jens

2013-12-01

82

Plant genetic engineering for biofuel production: towards affordable cellulosic ethanol  

Microsoft Academic Search

Biofuels provide a potential route to avoiding the global political instability and environmental issues that arise from reliance on petroleum. Currently, most biofuel is in the form of ethanol generated from starch or sugar, but this can meet only a limited fraction of global fuel requirements. Conversion of cellulosic biomass, which is both abundant and renewable, is a promising alternative.

Mariam B. Sticklen

2008-01-01

83

The impact of first-generation biofuels on the depletion of the global phosphorus reserve.  

PubMed

The large majority of biofuels to date is "first-generation" biofuel made from agricultural commodities. All first-generation biofuel production systems require phosphorus (P) fertilization. P is an essential plant nutrient, yet global reserves are finite. We argue that committing scarce P to biofuel production involves a trade-off between climate change mitigation and future food production. We examine biofuel production from seven types of feedstock, and find that biofuels at present consume around 2% of the global inorganic P fertilizer production. For all examined biofuels, with the possible exception of sugarcane, the contribution to P depletion exceeds the contribution to mitigating climate change. The relative benefits of biofuels can be increased through enhanced recycling of P, but high increases in P efficiency are required to balance climate change mitigation and P depletion impacts. We conclude that, with the current production systems, the production of first-generation biofuels compromises food production in the future. PMID:22351599

Hein, Lars; Leemans, Rik

2012-06-01

84

USING GIS TO DETERMINE PLANTABLE AREA FOR PRAIRIE SWITCHGRASS BIOFUEL PRODUCTION IN KENTUCKY RIGHTS-OF-WAY  

EPA Science Inventory

(1) The United States’ dependence on foreign fuel and other non-renewable resources has implications across disciplines including international relationships, the environment, and economics. Biofuels have been proposed as an alternative; however, land for biofuel product...

85

Trade-offs of water use for hydropower generation and biofuel production in the Zambezi basin in Mozambique  

NASA Astrophysics Data System (ADS)

Hydropower is the most important energy source in Mozambique, as in many other southern African countries. In the Zambezi basin, it is one of the major economic resources, and substantial hydropower development is envisaged for the next decades. In Mozambique, the extension of the large Cahora Bassa hydropower plant and the construction of several new facilities downstream are planned. Irrigated agriculture currently plays a minor role, but has a large potential due to available land and water resources. Irrigation development, especially for the production of biofuels, is an important government policy goal in Mozambique. This contribution assesses interrelations and trade-offs between these two development options with high dependence on water availability. Potential water demand for large-scale irrigated agriculture is estimated for a mix of possible biofuel crops in three scenarios with different irrigated area sizes. Impacts on river discharge and hydropower production in the Lower Zambezi and its tributaries under two projected future climates are simulated with a hydrological model and a reservoir operation and hydropower model. Trade-offs of increasing biofuel production with decreasing hydropower generation due to diminished discharge in the Zambezi River are investigated based on potential energy production, from hydropower and biofuels, and resulting gross revenues and net benefits. Results show that the impact of irrigation withdrawal on hydropower production is rather low due to the generally high water availability in the Zambezi River. In simulations with substantial irrigated areas, hydropower generation decreases by -2% as compared to a scenario with only small irrigated areas. The economic analyses suggest that the use of water for cultivation of biofuel crops in the Zambezi basin can generate higher economic benefits than the use of water for hydroelectric power production. If world oil prices stay at more than about 80 USD/barrel, then the production of biofuels for oil import substitution will yield strong benefits except for the least efficient producers. Producing biofuels for export is more challenging and requires highly efficient production. Generally, investment in irrigated agriculture is expected to have more impact on local economy and therefore poverty reduction than investment in hydropower development.

Stanzel, Philipp; Kling, Harald; Nicholson, Kit

2014-05-01

86

Biofuel production: an odyssey from metabolic engineering to fermentation scale-up  

PubMed Central

Metabolic engineering has developed microbial cell factories that can convert renewable carbon sources into biofuels. Current molecular biology tools can efficiently alter enzyme levels to redirect carbon fluxes toward biofuel production, but low product yield and titer in large bioreactors prevent the fulfillment of cheap biofuels. There are three major roadblocks preventing economical biofuel production. First, carbon fluxes from the substrate dissipate into a complex metabolic network. Besides the desired product, microbial hosts direct carbon flux to synthesize biomass, overflow metabolites, and heterologous enzymes. Second, microbial hosts need to oxidize a large portion of the substrate to generate both ATP and NAD(P)H to power biofuel synthesis. High cell maintenance, triggered by the metabolic burdens from genetic modifications, can significantly affect the ATP supply. Thereby, fermentation of advanced biofuels (such as biodiesel and hydrocarbons) often requires aerobic respiration to resolve the ATP shortage. Third, mass transfer limitations in large bioreactors create heterogeneous growth conditions and micro-environmental fluctuations (such as suboptimal O2 level and pH) that induce metabolic stresses and genetic instability. To overcome these limitations, fermentation engineering should merge with systems metabolic engineering. Modern fermentation engineers need to adopt new metabolic flux analysis tools that integrate kinetics, hydrodynamics, and 13C-proteomics, to reveal the dynamic physiologies of the microbial host under large bioreactor conditions. Based on metabolic analyses, fermentation engineers may employ rational pathway modifications, synthetic biology circuits, and bioreactor control algorithms to optimize large-scale biofuel production.

Hollinshead, Whitney; He, Lian; Tang, Yinjie J.

2014-01-01

87

Biofuel production: an odyssey from metabolic engineering to fermentation scale-up.  

PubMed

Metabolic engineering has developed microbial cell factories that can convert renewable carbon sources into biofuels. Current molecular biology tools can efficiently alter enzyme levels to redirect carbon fluxes toward biofuel production, but low product yield and titer in large bioreactors prevent the fulfillment of cheap biofuels. There are three major roadblocks preventing economical biofuel production. First, carbon fluxes from the substrate dissipate into a complex metabolic network. Besides the desired product, microbial hosts direct carbon flux to synthesize biomass, overflow metabolites, and heterologous enzymes. Second, microbial hosts need to oxidize a large portion of the substrate to generate both ATP and NAD(P)H to power biofuel synthesis. High cell maintenance, triggered by the metabolic burdens from genetic modifications, can significantly affect the ATP supply. Thereby, fermentation of advanced biofuels (such as biodiesel and hydrocarbons) often requires aerobic respiration to resolve the ATP shortage. Third, mass transfer limitations in large bioreactors create heterogeneous growth conditions and micro-environmental fluctuations (such as suboptimal O2 level and pH) that induce metabolic stresses and genetic instability. To overcome these limitations, fermentation engineering should merge with systems metabolic engineering. Modern fermentation engineers need to adopt new metabolic flux analysis tools that integrate kinetics, hydrodynamics, and (13)C-proteomics, to reveal the dynamic physiologies of the microbial host under large bioreactor conditions. Based on metabolic analyses, fermentation engineers may employ rational pathway modifications, synthetic biology circuits, and bioreactor control algorithms to optimize large-scale biofuel production. PMID:25071754

Hollinshead, Whitney; He, Lian; Tang, Yinjie J

2014-01-01

88

Biofuel, dairy production and beef in Brazil: competing claims on land use in São Paulo state.  

PubMed

This paper examines the competing claims on land use resulting from the expansion of biofuel production. Sugarcane for biofuel drives agrarian change in So Paulo state, which has become the major ethanol-producing region in Brazil. We analyse how the expansion of sugarcane-based ethanol in So Paulo state has impacted dairy and beef production. Historical changes in land use, production technologies, and product and land prices are described, as well as how these are linked to changing policies in Brazil. We argue that sugarcane/biofuel expansion should be understood in the context of the dynamics of other agricultural sectors and the long-term national political economy rather than as solely due to recent global demand for biofuel. This argument is based on a meticulous analysis of changes in three important sectors - sugarcane, dairy farming, and beef production - and the mutual interactions between these sectors. PMID:21125724

Novo, André Luiz Monteiro; Jansen, Kees; Slingerland, Maja; Giller, Ken

2010-01-01

89

Plant cell wall engineering: applications in biofuel production and improved human health.  

PubMed

Plant cell walls consist largely of cellulose, non-cellulosic polysaccharides and lignin. Concerted attempts are underway to convert wall polysaccharides from crop plant residues into renewable transport fuels and other valuable products, and to exploit the dietary benefits of cereal grain wall polysaccharides in human health. Attempts to improve plant performance for these applications have involved the manipulation of the levels and structures of wall components. Some successes in altering non-cellulosic polysaccharides has been achieved, but it would appear that drastic changes in cellulose are more difficult to engineer. Nevertheless, future prospects for both genetically modified (GM) and non-GM technologies to modify plant cell wall composition and structure remain bright, and will undoubtedly find applications beyond the current focus on human health and biofuel production. PMID:24679262

Burton, Rachel A; Fincher, Geoffrey B

2014-04-01

90

Structure of a three-domain sesquiterpene synthase: a prospective target for advanced biofuels production.  

PubMed

The sesquiterpene bisabolene was recently identified as a biosynthetic precursor to bisabolane, an advanced biofuel with physicochemical properties similar to those of D2 diesel. High-titer microbial bisabolene production was achieved using Abies grandis ?-bisabolene synthase (AgBIS). Here, we report the structure of AgBIS, a three-domain plant sesquiterpene synthase, crystallized in its apo form and bound to five different inhibitors. Structural and biochemical characterization of the AgBIS terpene synthase Class I active site leads us to propose a catalytic mechanism for the cyclization of farnesyl diphosphate into bisabolene via a bisabolyl cation intermediate. Further, we describe the nonfunctional AgBIS Class II active site whose high similarity to bifunctional diterpene synthases makes it an important link in understanding terpene synthase evolution. Practically, the AgBIS crystal structure is important in future protein engineering efforts to increase the microbial production of bisabolene. PMID:22153510

McAndrew, Ryan P; Peralta-Yahya, Pamela P; DeGiovanni, Andy; Pereira, Jose H; Hadi, Masood Z; Keasling, Jay D; Adams, Paul D

2011-12-01

91

Biofuel Production Datasets from DOE's Bioenergy Knowledge Discovery Framework (KDF)  

DOE Data Explorer

The Bioenergy Knowledge Discovery Framework invites users to discover the power of bioenergy through an interface that provides extensive access to research data and literature, GIS mapping tools, and collaborative networks. The Bioenergy KDF supports efforts to develop a robust and sustainable bioenergy industry. The KDF facilitates informed decision making by providing a means to synthesize, analyze, and visualize vast amounts of information in a relevant and succinct manner. It harnesses Web 2.0 and social networking technologies to build a collective knowledge system that can better examine the economic and environmental impacts of development options for biomass feedstock production, biorefineries, and related infrastructure. [copied from https://www.bioenergykdf.net/content/about]

Holdings include datasets, models, and maps. This is a very new resource, but the collections will grow due to both DOE contributions and individualsÆ data uploads. Currently the Biofuel Production collection includes 100 items. Most of these are categorized as literature, but six datasets and 16 models are listed.

92

Assessing regional hydrology and water quality implications of large-scale biofuel feedstock production in the Upper Mississippi River Basin.  

PubMed

A recent U.S. Department of Energy study estimated that more than one billion tons of biofuel feedstock could be produced by 2030 in the United States from increased corn yield, and changes in agricultural and forest residue management and land uses. To understand the implications of such increased production on water resources and stream quality at regional and local scales, we have applied a watershed model for the Upper Mississippi River Basin, where most of the current and future crop/residue-based biofuel production is expected. The model simulates changes in water quality (soil erosion, nitrogen and phosphorus loadings in streams) and resources (soil-water content, evapotranspiration, and runoff) under projected biofuel production versus the 2006 baseline year and a business-as-usual scenario. The basin average results suggest that the projected feedstock production could change the rate of evapotranspiration in the UMRB by approximately +2%, soil-water content by about -2%, and discharge to streams by -5% from the baseline scenario. However, unlike the impacts on regional water availability, the projected feedstock production has a mixed effect on water quality, resulting in 12% and 45% increases in annual suspended sediment and total phosphorus loadings, respectively, but a 3% decrease in total nitrogen loading. These differences in water quantity and quality are statistically significant (p < 0.05). The basin responses are further analyzed at monthly time steps and finer spatial scales to evaluate underlying physical processes, which would be essential for future optimization of environmentally sustainable biofuel productions. PMID:22827327

Demissie, Yonas; Yan, Eugene; Wu, May

2012-08-21

93

Protein engineering in designing tailored enzymes and microorganisms for biofuels production  

PubMed Central

Summary Lignocellulosic biofuels represent a sustainable, renewable, and the only foreseeable alternative energy source to transportation fossil fuels. However, the recalcitrant nature of lignocellulose poses technical hurdles to an economically viable biorefinery. Low enzymatic hydrolysis efficiency and low productivity, yield, and titer of biofuels are among the top cost contributors. Protein engineering has been used to improve the performances of lignocellulose-degrading enzymes, as well as proteins involved in biofuel synthesis pathways. Unlike its great success seen in other industrial applications, protein engineering has achieved only modest results in improving the lignocellulose-to-biofuels efficiency. This review will discuss the unique challenges that protein engineering faces in the process of converting lignocellulose to biofuels and how they are addressed by recent advances in this field.

Wen, Fei; Nair, Nikhil U; Zhao, Huimin

2009-01-01

94

The economic prospects of cellulosic biomass for biofuel production  

NASA Astrophysics Data System (ADS)

Alternative fuels for transportation have become the focus of intense policy debate and legislative action due to volatile oil prices, an unstable political environment in many major oil producing regions, increasing global demand, dwindling reserves of low-cost oil, and concerns over global warming. A major potential source of alternative fuels is biofuels produced from cellulosic biomass, which have a number of potential benefits. Recognizing these potential advantages, the Energy Independence and Security Act of 2007 has mandated 21 billion gallons of cellulosic/advanced biofuels per year by 2022. The United States needs 220-300 million tons of cellulosic biomass per year from the major sources such as agricultural residues, forestry and mill residues, herbaceous resources, and waste materials (supported by Biomass Crop Assistance Program) to meet these biofuel targets. My research addresses three key major questions concerning cellulosic biomass supply. The first paper analyzes cellulosic biomass availability in the United States and Canada. The estimated supply curves show that, at a price of 100 per ton, about 568 million metric tons of biomass is available in the United States, while 123 million metric tons is available in Canada. In fact, the 300 million tons of biomass required to meet EISA mandates can be supplied at a price of 50 per metric ton or lower. The second paper evaluates the farmers' perspective in growing new energy crops, such as switchgrass and miscanthus, in prime cropland, in pasture areas, or on marginal lands. My analysis evaluates how the farmers' returns from energy crops compare with those from other field crops and other agricultural land uses. The results suggest that perennial energy crops yielding at least 10 tons per acre annually will be competitive with a traditional corn-soybean rotation if crude oil prices are high (ranging from 88-178 per barrel over 2010-2019). If crude oil prices are low, then energy crops will not be competitive with existing crops, and additional subsidy support would be required. Among the states in the eastern half of US, the states of Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, and Virginia are found to be economically more suitable to cultivate perennial energy crops. The third paper estimates the optimal feedstock composition of annual and perennial feedstocks from a biorefinery's perspective. The objective function of the optimization model is to minimize the cumulative costs covering harvesting, transport, storage, and GHG costs, of biomass procurement over a biorefinery's productive period of 20 years subject to various constraints on land availability, feedstock availability, processing capacity, contracting needs and storage. The results suggest that the economic tradeoff is between higher production costs for dedicated energy crops and higher collection and transport costs for agricultural residues; the delivered costs of biomass drives the results. These tradeoffs are reflected in optimal spatial planting pattern as preferred by the biorefinery: energy crops are grown in fields closer to the biorefinery and agricultural residues can be sourced from fields farther away from the biorefinery. The optimization model also provides useful insights into the price premiums paid for annual and perennial feedstocks. For the parameters used in the case study, the energy crop price premium ranges from 2 to 8 per ton for fields located within a 10 mile radius. For agricultural residues, the price premiums range from 5 to 16 per ton within a 10-20 mile radius.

Kumarappan, Subbu

95

Development of an attached microalgal growth system for biofuel production.  

PubMed

Algal biofuel production has gained a renewed interest in recent years but is still not economically feasible due to several limitations related to algal culture. The objective of this study is to explore a novel attached culture system for growing the alga Chlorella sp. as biodiesel feedstock, with dairy manure wastewater being used as growth medium. Among supporting materials tested for algal attachment, polystyrene foam led to a firm attachment, high biomass yield (25.65 g/m(2), dry basis), and high fatty acid yield (2.31 g/m(2)). The biomass attached on the supporting material surface was harvested by scraping; the residual colonies left on the surface served as inoculum for regrowth. The algae regrowth on the colony-established surface resulted in a higher biomass yield than that from the initial growth on fresh surface due to the downtime saved for initial algal attachment. The 10-day regrowth culture resulted in a high biodiesel production potential with a fatty acid methyl esters yield of 2.59 g/m(2) and a productivity of 0.26 g/m(-2) day(-1). The attached algal culture also removed 61-79% total nitrogen and 62-93% total phosphorus from dairy manure wastewater, depending on different culture conditions. The biomass harvested from the attached growth system (through scraping) had a water content of 93.75%, similar to that harvested from suspended culture system (through centrifugation). Collectively, the attached algal culture system with polystyrene foam as a supporting material demonstrated a good performance in terms of biomass yield, biodiesel production potential, ease to harvest biomass, and physical robustness for reuse. PMID:19636552

Johnson, Michael B; Wen, Zhiyou

2010-01-01

96

BIOWINOL TECHNOLOGIES: A HYBRID GREEN PROCESS FOR BIOFUEL PRODUCTION ? PHASE 2  

EPA Science Inventory

The development of hollow fiber membrane (HFM) reactor will result in improved gas utilization that will positively impact overall process efficiencies. Successful completion of this project could result in the development of many decentralized biofuel production systems near ...

97

Reclaimed Water and Secondary Wastewater as Alternative Growing Media for Green Algae for Biofuel Production  

Microsoft Academic Search

The microalga Botryococcus braunii is one of many photosynthtic algae species being investigated as renewable feedstocks for production of biofuels. One key advantage of algae as biofuel feedstock, in view of the growing scarcity of fresh water worldwide, is the potential of algae to grow in low-quality water, including in the nutrient-containing effluents from wastewater-treatment plants. Indeed, algae could also

Sara S. Kuwahara; Joel L. Cuello

98

Review on biofuel oil and gas production processes from microalgae  

Microsoft Academic Search

Microalgae, as biomass, are a potential source of renewable energy, and they can be converted into energy such as biofuel oil and gas. This paper presents a brief review on the main conversion processes of microalgae becoming energy. Since microalgae have high water content, not all biomass energy conversion processes can be applied. By using thermochemical processes, oil and gas

Sarmidi Amin

2009-01-01

99

Engineering of microorganisms for the production of biofuels and perspectives based on systems metabolic engineering approaches.  

PubMed

The increasing oil price and environmental concerns caused by the use of fossil fuel have renewed our interest in utilizing biomass as a sustainable resource for the production of biofuel. It is however essential to develop high performance microbes that are capable of producing biofuels with very high efficiency in order to compete with the fossil fuel. Recently, the strategies for developing microbial strains by systems metabolic engineering, which can be considered as metabolic engineering integrated with systems biology and synthetic biology, have been developed. Systems metabolic engineering allows successful development of microbes that are capable of producing several different biofuels including bioethanol, biobutanol, alkane, and biodiesel, and even hydrogen. In this review, the approaches employed to develop efficient biofuel producers by metabolic engineering and systems metabolic engineering approaches are reviewed with relevant example cases. It is expected that systems metabolic engineering will be employed as an essential strategy for the development of microbial strains for industrial applications. PMID:21889585

Jang, Yu-Sin; Park, Jong Myoung; Choi, Sol; Choi, Yong Jun; Seung, Do Young; Cho, Jung Hee; Lee, Sang Yup

2012-01-01

100

The effect of biofuel production on swine farm methane and ammonia emissions.  

PubMed

Methane (CH) and ammonia (NH3) are emitted to the atmosphere during anaerobic processing of organic matter, and both gases have detrimental environmental effects. Methane conversion to biofuel production has been suggested to reduce CH4 emissions from animal manure processing systems. The purpose of this research is to evaluate the change in CH4 and NH3 emissions in an animal feeding operation due to biofuel production from the animal manure. Gas emissions were measured from swine farms differing only in their manure-management treatment systems (conventional vs. biofuel). By removing organic matter (i.e., carbon) from the biofuel farms' manure-processing lagoons, average annual CH4 emissions were decreased by 47% compared with the conventional farm. This represents a net 44% decrease in global warming potential (CO2 equivalent) by gases emitted from the biofuel farms compared with conventional farms. However, because of the reduction of methanogenesis and its reduced effect on the chemical conversion of ammonium (NH4+) to dinitrogen (N2) gas, NH3 emissions in the biofuel farms increased by 46% over the conventional farms. These studies show that what is considered an environmentally friendly technology had mixed results and that all components of a system should be studied when making changes to existing systems. PMID:21284295

Harper, Lowry A; Flesch, Thomas K; Weaver, Kim H; Wilson, John D

2010-01-01

101

Biofuel production system with operation flexibility: Evaluation of economic and environmental performance under external disturbance  

NASA Astrophysics Data System (ADS)

Biomass derived liquid hydrocarbon fuel (biofuel) has been accepted as an effective way to mitigate the reliance on petroleum and reduce the greenhouse gas emissions. An increasing demand for second generation biofuels, produced from ligno-cellulosic feedstock and compatible with current infrastructure and vehicle technologies, addresses two major challenges faced by the current US transportation sector: energy security and global warming. However, biofuel production is subject to internal disturbances (feedstock supply and commodity market) and external factors (energy market). The biofuel industry has also heavily relied on government subsidy during the early development stages. In this dissertation, I investigate how to improve the economic and environmental performance of biorefineries (and biofuel plant), as well as enhance its survivability under the external disturbances. Three types of disturbance are considered: (1) energy market fluctuation, (2) subsidy policy uncertainty, and (3) extreme weather conditions. All three factors are basically volatile, dynamic, and even unpredictable, which makes them difficult to model and have been largely ignored to date. Instead, biofuel industry and biofuel research are intensively focused on improving feedstock conversion efficiency and capital cost efficiency while assuming these advancements alone will successfully generate higher profit and thus foster the biofuel industry. The collapse of the largest corn ethanol biofuel company, Verasun Energy, in 2008 calls into question this efficiency-driven approach. A detailed analysis has revealed that although the corn ethanol plants operated by Verasun adopted the more efficient (i.e. higher ethanol yield per bushel of corn and lower capital cost) dry-mill technology, they could not maintain a fair profit margin under fluctuating market condition which made ethanol production unprofitable. This is because dry-mill plant converts a single type of biomass feedstock (corn grain) into a single primary product (ethanol). The traditional lower efficient (i.e. lower ethanol yield per bushel of corn and higher capital cost) wet-mill plant has a more diverse and adjustable product portfolio i.e. corn syrup, starch, and ethanol. The fact that only the dry-mill corn ethanol plants have bankrupted while the wet-mill corn ethanol plants have survived the late 2000s economy recession suggests that the higher conversion efficiency achieved by the dry-mill production mode has jeopardized operational flexibility, a design operational feature I agree that is indispensable for the biofuel plant's long term profit and viability. Based on the analysis of corn ethanol production, operational flexibility has been proposed as a key strategy for the next generation biofuel plants to improve its lifetime economic performance, as well as to enhance its survivability under external disturbances. This strategy requires the biofuel plant to adopt a flexible feedstock management, making it possible to utilize alternative types of biomass feedstock when the primary feedstock supply is disturbed. Biofuel plants also need to produce a wider range of final products that could meet the preference variation that either comes from the energy market or from the subsidy policy. Aspen Plus model based numerical simulations have been carried out for a thermochemical ethanol plant and a Fischer Tropsch plant (both are assumed to be located in southwest Indiana) to test this strategy under the external disturbances of extreme weather impact, different energy price projections and various subsidy policy combinations. For the thermochemical ethanol plant, effects of extreme weather conditions are mainly evaluated. It has been shown that this strategy could effectively increase the net present value of the biofuel plant and significantly decrease the GHG emission comparing with the traditional single-feedstock strategy, when the extreme weather conditions are considered. It has also been demonstrated that this strategy could significantly decrease the possibility for the bio

Kou, Nannan

102

Determining the global maximum biofuel production potential without conflicting with food and feed consumption  

NASA Astrophysics Data System (ADS)

This study tries to resolve the competition between food and biofuel by balancing the allocation between food and feed areas and biofuel areas for the entire world. The maximum energy production is calculated by determining the theoretical amount of energy that can be grown, once food and feed consumption is taken into account, based on the assumption that unprotected grass and woody lands and forest lands can be converted into cultivated lands. The total optimum land area for biofuel energy, 4,926.49 Mha, consists of corn, rapeseed, sugar beet, sugar cane, and grasses. When considering energy conversion efficiency, the maximum energy production is 520.5 EJ. Of this amount, 5.9 EJ can be identified with food and feed energy and 514.6 EJ can be identified with biofuel energy. This result is a theoretical value to illustrate the potential global land area for biofuel. The biofuel energy production per area of land in this study is calculated to be 0.12 EJ/Mha. With regards to the limitation in the degree of invasion by grass and woody land and forest land areas, if it is not more than 10 percent, the biofuel energy production can serve about 76 percent of energy demand for transportation in 2009. The total optimum land area is about 45 percent of global cultivated land area. Sensitivity analysis shows that the land area of corn, sweet sorghum, sugarcane, grass, and woody crops is sensitive to energy content. The land area of sweet sorghum and soybeans is sensitive to the land area for food and feed consumption. Also, the land area of corn, sugar beet, and sugarcane is sensitive to the potential crop land area. This study, done at the global level, can also apply in a local area by using local constraints.

Pumkaew, Watcharapol

103

Biofuels from Pyrolysis: Catalytic Biocrude Production in a Novel, Short-Contact Time Reactor  

SciTech Connect

Broad Funding Opportunity Announcement Project: RTI is developing a new pyrolysis process to convert second-generation biomass into biofuels in one simple step. Pyrolysis is the decomposition of substances by heating—the same process used to render wood into charcoal, caramelize sugar, and dry roast coffee and beans. RTI’s catalytic biomass pyrolysis differs from conventional flash pyrolysis in that its end product contains less oxygen, metals, and nitrogen—all of which contribute to corrosion, instability, and inefficiency in the fuel-production process. This technology is expected to easily integrate into the existing domestic petroleum refining infrastructure, making it an economically attractive option for biofuels production.

None

2010-01-01

104

Trends and sustainability criteria of the production and use of liquid biofuels  

Microsoft Academic Search

Environmental impacts associated with the use of fossil fuels, rising prices, potential limitations in supply and concerns about regional and national security are driving the development and use of biomass for bioenergy, biofuels and bioproducts. However, the use of biomass does not automatically imply that its production, conversion and use are sustainable. Conflicts between various ecosystem services (economic production of

A. Markevi?ius; V. Katinas; E. Perednis; M. Tamašauskien?

2010-01-01

105

Heterologous expression of plant cell wall degrading enzymes for effective production of cellulosic biofuels.  

PubMed

A major technical challenge in the cost-effective production of cellulosic biofuel is the need to lower the cost of plant cell wall degrading enzymes (PCDE), which is required for the production of sugars from biomass. Several competitive, low-cost technologies have been developed to produce PCDE in different host organisms such as Escherichia coli, Zymomonas mobilis, and plant. Selection of an ideal host organism is very important, because each host organism has its own unique features. Synthetic biology-aided tools enable heterologous expression of PCDE in recombinant E. coli or Z. mobilis and allow successful consolidated bioprocessing (CBP) in these microorganisms. In-planta expression provides an opportunity to simplify the process of enzyme production and plant biomass processing and leads to self-deconstruction of plant cell walls. Although the future of currently available technologies is difficult to predict, a complete and viable platform will most likely be available through the integration of the existing approaches with the development of breakthrough technologies. PMID:22911272

Jung, Sang-Kyu; Parisutham, Vinuselvi; Jeong, Seong Hun; Lee, Sung Kuk

2012-01-01

106

Heterologous Expression of Plant Cell Wall Degrading Enzymes for Effective Production of Cellulosic Biofuels  

PubMed Central

A major technical challenge in the cost-effective production of cellulosic biofuel is the need to lower the cost of plant cell wall degrading enzymes (PCDE), which is required for the production of sugars from biomass. Several competitive, low-cost technologies have been developed to produce PCDE in different host organisms such as Escherichia coli, Zymomonas mobilis, and plant. Selection of an ideal host organism is very important, because each host organism has its own unique features. Synthetic biology-aided tools enable heterologous expression of PCDE in recombinant E. coli or Z. mobilis and allow successful consolidated bioprocessing (CBP) in these microorganisms. In-planta expression provides an opportunity to simplify the process of enzyme production and plant biomass processing and leads to self-deconstruction of plant cell walls. Although the future of currently available technologies is difficult to predict, a complete and viable platform will most likely be available through the integration of the existing approaches with the development of breakthrough technologies.

Jung, Sang-Kyu; Parisutham, Vinuselvi; Jeong, Seong Hun; Lee, Sung Kuk

2012-01-01

107

An auto-inducible mechanism for ionic liquid resistance in microbial biofuel production.  

PubMed

Ionic liquids (ILs) are emerging as superior solvents for numerous industrial applications, including the pretreatment of biomass for the microbial production of biofuels. However, some of the most effective ILs used to solubilize cellulose inhibit microbial growth, decreasing efficiency in the overall process. Here we identify an IL-resistance mechanism consisting of two adjacent genes from Enterobacter lignolyticus, a rain forest soil bacterium that is tolerant to an imidazolium-based IL. These genes retain their full functionality when transferred to an Escherichia coli biofuel host, with IL resistance established by an inner membrane transporter, regulated by an IL-inducible repressor. Expression of the transporter is dynamically adjusted in direct response to IL, enabling growth and biofuel production at levels of IL that are toxic to native strains. This natural auto-regulatory system provides the basis for engineering IL-tolerant microbes, which should accelerate progress towards effective conversion of lignocellulosic biomass to fuels and renewable chemicals. PMID:24667370

Ruegg, Thomas L; Kim, Eun-Mi; Simmons, Blake A; Keasling, Jay D; Singer, Steven W; Soon Lee, Taek; Thelen, Michael P

2014-01-01

108

Life Cycle Assessment (LCA) of the biofuel production process from sunflower oil, rapeseed oil and soybean oil  

Microsoft Academic Search

Once ratified the Kyoto protocol, Spain arises the great challenge of reducing the emissions of greenhouse gases. Among the measures proposed is the introduction of biofuels in the market, both for the transport sector and for the production of heat. This paper compares the environmental impact from the production of biofuels whose origin is the oil obtained from sunflower, rapeseed

J. F. Sanz Requena; A. C. Guimaraes; S. Quirós Alpera; E. Relea Gangas; S. Hernandez-Navarro; L. M. Navas Gracia; J. Martin-Gil; H. Fresneda Cuesta

2011-01-01

109

Biofuels from Lignocellulosic Biomass  

Microsoft Academic Search

\\u000a Biomass feedstock, which is mainly lignocellulose, has considerable potential to contribute to the future production of biofuels\\u000a and to the mitigation of carbon dioxide emissions. Several challenges exist in the production, harvesting, and conversion\\u000a aspects of lignocellulose, and these must be resolved in order to reach economic viability. A broad array of research projects\\u000a are underway to address the technical

Xiaorong Wu; James McLaren; Ron Madl; Donghai Wang

110

A Thermophilic Ionic Liquid-Tolerant Cellulase Cocktail for the Production of Cellulosic Biofuels  

PubMed Central

Generation of biofuels from sugars in lignocellulosic biomass is a promising alternative to liquid fossil fuels, but efficient and inexpensive bioprocessing configurations must be developed to make this technology commercially viable. One of the major barriers to commercialization is the recalcitrance of plant cell wall polysaccharides to enzymatic hydrolysis. Biomass pretreatment with ionic liquids (ILs) enables efficient saccharification of biomass, but residual ILs inhibit both saccharification and microbial fuel production, requiring extensive washing after IL pretreatment. Pretreatment itself can also produce biomass-derived inhibitory compounds that reduce microbial fuel production. Therefore, there are multiple points in the process from biomass to biofuel production that must be interrogated and optimized to maximize fuel production. Here, we report the development of an IL-tolerant cellulase cocktail by combining thermophilic bacterial glycoside hydrolases produced by a mixed consortia with recombinant glycoside hydrolases. This enzymatic cocktail saccharifies IL-pretreated biomass at higher temperatures and in the presence of much higher IL concentrations than commercial fungal cocktails. Sugars obtained from saccharification of IL-pretreated switchgrass using this cocktail can be converted into biodiesel (fatty acid ethyl-esters or FAEEs) by a metabolically engineered strain of E. coli. During these studies, we found that this biodiesel-producing E. coli strain was sensitive to ILs and inhibitors released by saccharification. This cocktail will enable the development of novel biomass to biofuel bioprocessing configurations that may overcome some of the barriers to production of inexpensive cellulosic biofuels.

Park, Joshua I.; Steen, Eric J.; Burd, Helcio; Evans, Sophia S.; Redding-Johnson, Alyssa M.; Batth, Tanveer; Benke, Peter I.; D'haeseleer, Patrik; Sun, Ning; Sale, Kenneth L.; Keasling, Jay D.; Lee, Taek Soon; Petzold, Christopher J.; Mukhopadhyay, Aindrila; Singer, Steven W.; Simmons, Blake A.; Gladden, John M.

2012-01-01

111

A thermophilic ionic liquid-tolerant cellulase cocktail for the production of cellulosic biofuels.  

PubMed

Generation of biofuels from sugars in lignocellulosic biomass is a promising alternative to liquid fossil fuels, but efficient and inexpensive bioprocessing configurations must be developed to make this technology commercially viable. One of the major barriers to commercialization is the recalcitrance of plant cell wall polysaccharides to enzymatic hydrolysis. Biomass pretreatment with ionic liquids (ILs) enables efficient saccharification of biomass, but residual ILs inhibit both saccharification and microbial fuel production, requiring extensive washing after IL pretreatment. Pretreatment itself can also produce biomass-derived inhibitory compounds that reduce microbial fuel production. Therefore, there are multiple points in the process from biomass to biofuel production that must be interrogated and optimized to maximize fuel production. Here, we report the development of an IL-tolerant cellulase cocktail by combining thermophilic bacterial glycoside hydrolases produced by a mixed consortia with recombinant glycoside hydrolases. This enzymatic cocktail saccharifies IL-pretreated biomass at higher temperatures and in the presence of much higher IL concentrations than commercial fungal cocktails. Sugars obtained from saccharification of IL-pretreated switchgrass using this cocktail can be converted into biodiesel (fatty acid ethyl-esters or FAEEs) by a metabolically engineered strain of E. coli. During these studies, we found that this biodiesel-producing E. coli strain was sensitive to ILs and inhibitors released by saccharification. This cocktail will enable the development of novel biomass to biofuel bioprocessing configurations that may overcome some of the barriers to production of inexpensive cellulosic biofuels. PMID:22649505

Park, Joshua I; Steen, Eric J; Burd, Helcio; Evans, Sophia S; Redding-Johnson, Alyssa M; Batth, Tanveer; Benke, Peter I; D'haeseleer, Patrik; Sun, Ning; Sale, Kenneth L; Keasling, Jay D; Lee, Taek Soon; Petzold, Christopher J; Mukhopadhyay, Aindrila; Singer, Steven W; Simmons, Blake A; Gladden, John M

2012-01-01

112

Modeling Regional Groundwater Implications of Biofuel Crop Production in the Great Lakes Region  

NASA Astrophysics Data System (ADS)

In response to a growing call for renewable sources of energy that do not compete directly with food resources, the use of second-generation 'cellulosic' biofuel feedstocks has gained much attention in recent years. The push to advance the technologies that would make such a transformation possible is motivated by the United States Renewable Fuel Standard mandate to produce 36 billion gallons of biofuels by 2022, an increase of 334 percent from 2009. Many different crops, including maize, miscanthus, switchgrass, and poplar have shown promise as cellulosic feedstocks, and in an attempt to supply the needed biomass to meet the 2022 mandate, production of these crops have been on the rise. Yet little is known about the sustainability of large-scale conversion of land to cellulosic biofuel crop production; more research is needed to understand the effects that these crops will have on the quality and quantity of groundwater. This study presents a model scale-up approach to address three questions: What are the hydrologic and nutrient demands of the primary biofuel crops? Which biofuel crops are more water efficient in terms of demand verses energy produced? What are the types and availabilities of land to expand production of these biofuel crops? To answer these questions, we apply a point-based crop dynamics model in combination with a regional-scale hydrologic model, parameterized using stream discharge and chemistry data collected from two representative watersheds in Wisconsin. Approximately 17 stream sites in each watershed are selected for data collection for model parameterization, including stream discharge, nutrient concentrations, and basic chemical characteristics. We then use the System Approach to Land Use Sustainability (SALUS) model, which predicts crop growth under varying soil and climate conditions, to drive vegetation dynamics and groundwater transport of nutrients within the Integrated Landscape Hydrology Model (ILHM). ILHM predictions of stream discharge and baseflow delivery of nutrients are then compared to field data to validate model predictions.

Parish, A.; Kendall, A. D.; Basso, B.; Hyndman, D. W.

2013-12-01

113

Applications and perspectives of multi-parameter flow cytometry to microbial biofuels production processes.  

PubMed

Conventional microbiology methods used to monitor microbial biofuels production are based on off-line analyses. The analyses are, unfortunately, insufficient for bioprocess optimization. Real time process control strategies, such as flow cytometry (FC), can be used to monitor bioprocess development (at-line) by providing single cell information that improves process model formulation and validation. This paper reviews the current uses and potential applications of FC in biodiesel, bioethanol, biomethane, biohydrogen and fuel cell processes. By highlighting the inherent accuracy and robustness of the technique for a range of biofuel processing parameters, more robust monitoring and control may be implemented to enhance process efficiency. PMID:22257766

da Silva, Teresa Lopes; Roseiro, José Carlos; Reis, Alberto

2012-04-01

114

Watermelon juice: a promising feedstock supplement, diluent, and nitrogen supplement for ethanol biofuel production  

Microsoft Academic Search

BACKGROUND: Two economic factors make watermelon worthy of consideration as a feedstock for ethanol biofuel production. First, about 20% of each annual watermelon crop is left in the field because of surface blemishes or because they are misshapen; currently these are lost to growers as a source of revenue. Second, the neutraceutical value of lycopene and L-citrulline obtained from watermelon

Wayne W Fish; Benny D Bruton; Vincent M Russo

2009-01-01

115

Biomass to dimethyl ether by gasification\\/synthesis technology—an alternative biofuel production route  

Microsoft Academic Search

Technical and economic analysis was done for the biomass to dimethyl ether (DME) technology to promote the gasification\\/synthesis\\u000a route for biofuel production and its application as a fossil fuel substitute. The technology of biomass gasification\\/synthesis\\u000a has obvious advantages, including production flexibility, environmental friendliness, economic feasibility, and application\\u000a versatility. Biomass gasification\\/synthesis technology integrates bio-DME synthesis, fertilizer production, electricity generation,\\u000a and waste

Tiejun Wang; Yuping Li; Longlong Ma; Chuangzhi Wu

2011-01-01

116

Tradeoffs and synergies between biofuel production and large-scale solar infrastructure in deserts  

NASA Astrophysics Data System (ADS)

Solar energy installations in deserts are on the rise, fueled by technological advances and policy changes. Deserts, with a combination of high solar radiation and availability of large areas unusable for crop production are ideal locations for large scale solar installations. For efficient power generation, solar infrastructures require large amounts of water for operation (mostly for cleaning panels and dust suppression), leading to significant moisture additions to desert soil. A pertinent question is how to use the moisture inputs for sustainable agriculture/biofuel production. We investigated the water requirements for large solar infrastructures in North American deserts and explored the possibilities for integrating biofuel production with solar infrastructure. In co-located systems the possible decline in yields due to shading by solar panels may be offsetted by the benefits of periodic water addition to biofuel crops, simpler dust management and more efficient power generation in solar installations, and decreased impacts on natural habitats and scarce resources in deserts. In particular, we evaluated the potential to integrate solar infrastructure with biomass feedstocks that grow in arid and semi-arid lands (Agave Spp), which are found to produce high yields with minimal water inputs. To this end, we conducted detailed life cycle analysis for these coupled agave biofuel - solar energy systems to explore the tradeoffs and synergies, in the context of energy input-output, water use and carbon emissions.

Ravi, S.; Lobell, D. B.; Field, C. B.

2012-12-01

117

Brown rot fungal early stage decay mechanism as a biological pretreatment for softwood biomass in biofuel production  

Microsoft Academic Search

A current barrier to the large-scale production of lignocellulosic biofuels is the cost associated with the energy and chemical inputs required for feedstock pretreatment and hydrolysis. The use of controlled partial biological degradation to replace elements of the current pretreatment technologies would offer tangible energy and cost benefits to the whole biofuel process. It has been known for some time

Michael J. Ray; David J. Leak; Pietro D. Spanu; Richard J. Murphy

2010-01-01

118

Biofuel production from crude palm oil with supercritical alcohols: comparative LCA studies.  

PubMed

A recent life cycle assessment (LCA) reported that biodiesel production in supercritical alcohols (SCA) produces a higher environmental load than the homogeneous catalytic process because an enormous amount of energy is required to recover excess alcohol. However, the excess alcohol could be dramatically reduced by increasing the operating temperature to 400°C; although the product would have to be considered as an alternative biofuel instead of biodiesel. A comparative LCA of the biodiesel production in two SCA at 300°C (C-SCA) and novel biofuel production in the same two SCA at 400°C (N-SCA) is presented. It was clear that the N-SCA process produces a dramatically reduced environmental load over that of the C-SCA process due to a lower amount of excess alcohol being used. The N-SCA process could be improved in terms of its environmental impact by changing from fossil fuel to biomass-based fuels for the steam generation. PMID:22776259

Sawangkeaw, Ruengwit; Teeravitud, Sunsanee; Piumsomboon, Pornpote; Ngamprasertsith, Somkiat

2012-09-01

119

Identification and microbial production of a terpene-based advanced biofuel  

PubMed Central

Rising petroleum costs, trade imbalances and environmental concerns have stimulated efforts to advance the microbial production of fuels from lignocellulosic biomass. Here we identify a novel biosynthetic alternative to D2 diesel fuel, bisabolane, and engineer microbial platforms for the production of its immediate precursor, bisabolene. First, we identify bisabolane as an alternative to D2 diesel by measuring the fuel properties of chemically hydrogenated commercial bisabolene. Then, via a combination of enzyme screening and metabolic engineering, we obtain a more than tenfold increase in bisabolene titers in Escherichia coli to >900 mg l?1. We produce bisabolene in Saccharomyces cerevisiae (>900 mg l?1), a widely used platform for the production of ethanol. Finally, we chemically hydrogenate biosynthetic bisabolene into bisabolane. This work presents a framework for the identification of novel terpene-based advanced biofuels and the rapid engineering of microbial farnesyl diphosphate-overproducing platforms for the production of biofuels.

Peralta-Yahya, Pamela P.; Ouellet, Mario; Chan, Rossana; Mukhopadhyay, Aindrila; Keasling, Jay D.; Lee, Taek Soon

2011-01-01

120

A High-Resolution National Microalgae Biofuel Production and Resource Assessment  

NASA Astrophysics Data System (ADS)

Microalgae are receiving increased global attention as a potential sustainable "energy crop" for biofuel production. An important step to realizing the potential of algae is quantifying the demands commercial-scale algal biofuel production will place on available resources. We present a high-resolution national-scale spatiotemporal assessment that begins to answer fundamental questions of where sustainable production can occur, what types and quantities of water, land, and nutrients are required, and how much energy is produced. A series of coupled model components were developed at a high spatiotemporal scale on the basis of the dominant biophysical processes affecting algal growth. Land suitable for open pond microalgae production consisting of 1200 acres per unit farm is identified using a multi-criteria land suitability model. Physics-based biomass growth and pond temperature models are then are used with location-specific meteorological and topographic data at 89,756 suitable unit farms to estimate 30-years of hourly biofuel production, nutrient requirements, and multi-source consumptive water demand. These resource requirements are compared with available resource supply and transport constraints to prioritize potential locations for sustainable microalgae feedstock production and evaluate the associated tradeoffs between production, resources, and economics.

Wigmosta, M.; Coleman, A.; Skaggs, R.; Venteris, E.

2012-12-01

121

Production and harvesting of microalgae for wastewater treatment, biofuels, and bioproducts.  

PubMed

The integration of microalgae-based biofuel and bioproducts production with wastewater treatment has major advantages for both industries. However, major challenges to the implementation of an integrated system include the large-scale production of algae and the harvesting of microalgae in a way that allows for downstream processing to produce biofuels and other bioproducts of value. Although the majority of algal production systems use suspended cultures in either open ponds or closed reactors, the use of attached cultures may offer several advantages. With regard to harvesting methods, better understanding and control of autoflocculation and bioflocculation could improve performance and reduce chemical addition requirements for conventional mechanical methods that include centrifugation, tangential filtration, gravity sedimentation, and dissolved air flotation. There are many approaches currently used by companies and industries using clean water at laboratory, bench, and pilot scale; however, large-scale systems for controlled algae production and/or harvesting for wastewater treatment and subsequent processing for bioproducts are lacking. Further investigation and development of large-scale production and harvesting methods for biofuels and bioproducts are necessary, particularly with less studied but promising approaches such as those involving attached algal biofilm cultures. PMID:21664266

Christenson, Logan; Sims, Ronald

2011-01-01

122

Biofuel production potentials in Europe: Sustainable use of cultivated land and pastures. Part I: Land productivity potentials  

Microsoft Academic Search

IIASA's agro-ecological zones modelling framework has been extended for biofuel productivity assessments distinguishing five main groups of feedstocks covering a wide range of agronomic conditions and energy production pathways, namely: woody lignocellulosic plants, herbaceous lignocellulosic plants, oil crops, starch crops and sugar crops. A uniform Pan-European land resources database was compiled at the spatial resolution of 1km2. Suitability and productivity

Günther Fischer; Sylvia Prieler; Harrij van Velthuizen; Sander M. Lensink; Marc Londo; Marc de Wit

2010-01-01

123

Predicting Potential Global Distributions of Two Miscanthus Grasses: Implications for Horticulture, Biofuel Production, and Biological Invasions  

PubMed Central

In many regions, large proportions of the naturalized and invasive non-native floras were originally introduced deliberately by humans. Pest risk assessments are now used in many jurisdictions to regulate the importation of species and usually include an estimation of the potential distribution in the import area. Two species of Asian grass (Miscanthus sacchariflorus and M. sinensis) that were originally introduced to North America as ornamental plants have since escaped cultivation. These species and their hybrid offspring are now receiving attention for large-scale production as biofuel crops in North America and elsewhere. We evaluated their potential global climate suitability for cultivation and potential invasion using the niche model CLIMEX and evaluated the models’ sensitivity to the parameter values. We then compared the sensitivity of projections of future climatically suitable area under two climate models and two emissions scenarios. The models indicate that the species have been introduced to most of the potential global climatically suitable areas in the northern but not the southern hemisphere. The more narrowly distributed species (M. sacchariflorus) is more sensitive to changes in model parameters, which could have implications for modelling species of conservation concern. Climate projections indicate likely contractions in potential range in the south, but expansions in the north, particularly in introduced areas where biomass production trials are under way. Climate sensitivity analysis shows that projections differ more between the selected climate change models than between the selected emissions scenarios. Local-scale assessments are required to overlay suitable habitat with climate projections to estimate areas of cultivation potential and invasion risk.

Hager, Heather A.; Sinasac, Sarah E.; Gedalof, Ze'ev; Newman, Jonathan A.

2014-01-01

124

Monster potential meets potential monster: pros and cons of deploying genetically modified microalgae for biofuels production  

PubMed Central

Biofuels production from microalgae attracts much attention but remains an unproven technology. We explore routes to enhance production through modifications to a range of generic microalgal physiological characteristics. Our analysis shows that biofuels production may be enhanced ca fivefold through genetic modification (GM) of factors affecting growth rate, respiration, photoacclimation, photosynthesis efficiency and the minimum cell quotas for nitrogen and phosphorous (N : C and P : C). However, simulations indicate that the ideal GM microalgae for commercial deployment could, on escape to the environment, become a harmful algal bloom species par excellence, with attendant risks to ecosystems and livelihoods. In large measure, this is because an organism able to produce carbohydrate and/or lipid at high rates, providing stock metabolites for biofuels production, will also be able to attain a stoichiometric composition that will be far from optimal as food for the support of zooplankton growth. This composition could suppress or even halt the grazing activity that would otherwise control the microalgal growth in nature. In consequence, we recommend that the genetic manipulation of microalgae, with inherent consequences on a scale comparable to geoengineering, should be considered under strict international regulation.

Flynn, K. J.; Mitra, A.; Greenwell, H. C.; Sui, J.

2013-01-01

125

Toward cell-free biofuel production: Stable immobilization of oligomeric enzymes.  

PubMed

To overcome the main challenges facing alcohol-based biofuel production, we propose an alternate simplified biofuel production scheme based on a cell-free immobilized enzyme system. In this paper, we measured the activity of two tetrameric enzymes, a control enzyme with a colorimetric assay, ?-galactosidase, and an alcohol-producing enzyme, alcohol dehydrogenase, immobilized on multiple surface curvatures and chemistries. Several solid supports including silica nanoparticles (convex), mesopourous silica (concave), diatomaceous earth (concave), and methacrylate (concave) were examined. High conversion rates and low protein leaching was achieved by covalent immobilization of both enzymes on methacrylate resin. Alcohol dehydrogenase (ADH) exhibited long-term stability and over 80% conversion of aldehyde to alcohol over 16 days of batch cycles. The complete reaction scheme for the conversion of acid to aldehyde to alcohol was demonstrated in vitro by immobilizing ADH with keto-acid decarboxylase free in solution. PMID:24449684

Grimaldi, J; Collins, C H; Belfort, G

2014-01-01

126

Enhanced biofuel production through coupled acetic acid and xylose consumption by engineered yeast.  

PubMed

The anticipation for substituting conventional fossil fuels with cellulosic biofuels is growing in the face of increasing demand for energy and rising concerns of greenhouse gas emissions. However, commercial production of cellulosic biofuel has been hampered by inefficient fermentation of xylose and the toxicity of acetic acid, which constitute substantial portions of cellulosic biomass. Here we use a redox balancing strategy to enable efficient xylose fermentation and simultaneous in situ detoxification of cellulosic feedstocks. By combining a nicotinamide adenine dinucleotide (NADH)-consuming acetate consumption pathway and an NADH-producing xylose utilization pathway, engineered yeast converts cellulosic sugars and toxic levels of acetate together into ethanol under anaerobic conditions. The results demonstrate a breakthrough in making efficient use of carbon compounds in cellulosic biomass and present an innovative strategy for metabolic engineering whereby an undesirable redox state can be exploited to drive desirable metabolic reactions, even improving productivity and yield. PMID:24105024

Wei, Na; Quarterman, Josh; Kim, Soo Rin; Cate, Jamie H D; Jin, Yong-Su

2013-01-01

127

Microbial advanced biofuels production: overcoming emulsification challenges for large-scale operation.  

PubMed

Isoprenoids and alkanes produced and secreted by microorganisms are emerging as an alternative biofuel for diesel and jet fuel replacements. In a similar way as for other bioprocesses comprising an organic liquid phase, the presence of microorganisms, medium composition, and process conditions may result in emulsion formation during fermentation, hindering product recovery. At the same time, a low-cost production process overcoming this challenge is required to make these advanced biofuels a feasible alternative. We review the main mechanisms and causes of emulsion formation during fermentation, because a better understanding on the microscale can give insights into how to improve large-scale processes and the process technology options that can address these challenges. PMID:24630476

Heeres, Arjan S; Picone, Carolina S F; van der Wielen, Luuk A M; Cunha, Rosiane L; Cuellar, Maria C

2014-04-01

128

The challenge of enzyme cost in the production of lignocellulosic biofuels.  

PubMed

With the aim of understanding the contribution of enzymes to the cost of lignocellulosic biofuels, we constructed a techno-economic model for the production of fungal cellulases. We found that the cost of producing enzymes was much higher than that commonly assumed in the literature. For example, the cost contribution of enzymes to ethanol produced by the conversion of corn stover was found to be $0.68/gal if the sugars in the biomass could be converted at maximum theoretical yields, and $1.47/gal if the yields were based on saccharification and fermentation yields that have been previously reported in the scientific literature. We performed a sensitivity analysis to study the effect of feedstock prices and fermentation times on the cost contribution of enzymes to ethanol price. We conclude that a significant effort is still required to lower the contribution of enzymes to biofuel production costs. PMID:22095526

Klein-Marcuschamer, Daniel; Oleskowicz-Popiel, Piotr; Simmons, Blake A; Blanch, Harvey W

2012-04-01

129

From fields to fuels: recent advances in the microbial production of biofuels.  

PubMed

Amid grave concerns over global climate change and with increasingly strained access to fossil fuels, the synthetic biology community has stepped up to the challenge of developing microbial platforms for the production of advanced biofuels. The adoption of gasoline, diesel, and jet fuel alternatives derived from microbial sources has the potential to significantly limit net greenhouse gas emissions. In this effort, great strides have been made in recent years toward the engineering of microorganisms to produce transportation fuels derived from alcohol, fatty acid, and isoprenoid biosynthesis. We provide an overview of the biosynthetic pathways devised in the strain development of biofuel-producing microorganisms. We also highlight many of the commonly used and newly devised engineering strategies that have been employed to identify and overcome pathway bottlenecks and problems of toxicity to maximize production titers. PMID:23656227

Kung, Yan; Runguphan, Weerawat; Keasling, Jay D

2012-11-16

130

Production of biofuel from waste cooking palm oil using nanocrystalline zeolite as catalyst: Process optimization studies  

Microsoft Academic Search

The catalytic cracking of waste cooking palm oil to biofuel was studied over different types of nano-crystalline zeolite catalysts in a fixed bed reactor. The effect of reaction temperature (400–500°C), catalyst-to-oil ratio (6–14) and catalyst pore size of different nanocrystalline zeolites (0.54–0.80nm) were studied over the conversion of waste cooking palm oil, yields of Organic Liquid Product (OLP) and gasoline

Niken Taufiqurrahmi; Abdul Rahman Mohamed; Subhash Bhatia

2011-01-01

131

Synergistic temperature and ethanol effect on Saccharomyces cerevisiae dynamic behaviour in ethanol bio-fuel production  

Microsoft Academic Search

The impact of ethanol and temperature on the dynamic behaviour of Saccharomyces cerevisiae in ethanol biofuel production was studied using an isothermal fed-batch process at five different temperatures. Fermentation parameters and kinetics were quantified. The best performances were found at 30 and 33°C around 120 g l -1 ethanol produced in 30 h with a slight benefit for growth at 30°C and for

A. S. Aldiguier; S. Alfenore; X. Cameleyre; G. Goma; J. L. Uribelarrea; S. E. Guillouet; C. Molina-Jouve

2004-01-01

132

Incorporation of process integration into life cycle analysis for the production of biofuels  

Microsoft Academic Search

This article presents a new approach for incorporating process-integration tools into life cycle analysis (LCA) for biofuel\\u000a production. Process synthesis techniques using mass- and energy-integration tools are employed to generate various scenarios\\u000a for reducing mass and energy consumption in the process. The global implications of these changes and the associated trade-offs\\u000a are assessed using the LCA tool: GREET. The developed

Pascale Chouinard-Dussault; Laura Bradt; José María Ponce-Ortega; Mahmoud M. El-Halwagi

133

Production of biofuels via co-processing in conventional refining processes  

Microsoft Academic Search

Production of second-generation biofuels via gasification followed by Fischer–Tropsch synthesis is receiving increased attention due to the high-quality fuels produced. Although this process scheme produces fuel components compatible with conventional fossil fuels, the high-investment cost associated with its commercial application renders this option economically unfeasible. For this reason other process schemes are explored, primarily aiming to lower investment costs. Such

A. A. Lappas; S. Bezergianni; I. A. Vasalos

2009-01-01

134

Production of advanced biofuels: Coprocessing of upgraded pyrolysis oil in standard refinery units  

Microsoft Academic Search

One of the possible process options for the production of advanced biofuels is the co-processing of upgraded pyrolysis oil in standard refineries. The applicability of hydrodeoxygenation (HDO) was studied as a pyrolysis oil upgrading step to allow FCC co-processing. Different HDO reaction end temperatures (230–340°C) were evaluated in a 5L autoclave, keeping the other process conditions constant (total 290bar, 5wt.%

F. de Miguel Mercader; M. J. Groeneveld; S. R. A. Kersten; C. J. Schaverien; J. A. Hogendoorn

2010-01-01

135

Forecasting energy security impacts of biofuels using regional climate models  

NASA Astrophysics Data System (ADS)

Production of biofuels in the U.S. is growing rapidly, with corn providing the dominant feedstock for current production and corn stover potentially providing a critical feedstock source for future cellulosic ethanol production. While production of domestic biofuels is thought to improve energy security, future changes in climate may impact crop yield variability and erode the energy security benefits of biofuels. Here we examine future yield variability for corn and soy using RegCM regional climate data from NARCAPP, historical agronomic data, and statistical models of yield variability. Our simulations of historical yield anomalies using monthly temperature and precipitation data from RegCM show robust relationships to observed yield anomalies. Simulations of future yield anomalies show increased yield variability relative to historical yield variability in the region of high corn production. Since variability in energy supply is a critical concern for energy security we suggest that the climate-induced yield variability on critical biofuels feedstocks be explored more widely.

Yang, X.; Campbell, E.; Snyder, M. A.; Sloan, L.; Kueppers, L. M.

2010-12-01

136

Microalgae for the production of bulk chemicals and biofuels  

Microsoft Academic Search

The feasibility of microalgae production for biodiesel was discussed. Although algae are not yet produced at large scale for bulk applications, there are opportunities to develop this process in a sustainable way. It remains unlikely, however, that the process will be developed for biodiesel as the only end product from microalgae. In order to develop a more sustainable and economically

Rene H Wijffels; Maria J Barbosa; Michel H M Eppink

2010-01-01

137

Effects on carbon and nitrogen emissions due to swine manure removal for biofuel production.  

PubMed

Methane (CH) and ammonia (NH) are emitted from swine-manure processing lagoons, contributing to global climate change and reducing air quality. Manure diverted to biofuel production is proposed as a means to reduce CH emissions. At a swine confined animal feeding operation in the U.S. Central Great Basin, animal manure was diverted from 12 farms to a biofuel facility and converted to methanol. Ammonia emissions were determined using the De Visscher Model from measured data of dissolved lagoon ammoniacal N concentrations, pH, temperature, and wind speed at the lagoon sites. Other lagoon gas emissions were measured with subsurface gas collection devices and gas chromatography analysis. During 2 yr of study, CO and CH emissions from the primary lagoons decreased 11 and 12%, respectfully, as a result of the biofuel process, compared with concurrently measured control lagoon emissions. Ammonia emissions increased 47% compared with control lagoons. The reduction of CH and increase in NH emissions agrees with a short-term study measured at this location by Lagrangian inverse dispersion analysis. The increase in NH emissions was primarily due to an increase in lagoon solution pH attributable to decreased methanogenesis. Also observed due to biofuel production was a 20% decrease in conversion of total ammoniacal N to N, a secondary process for the removal of N in anaerobic waste lagoons. The increase in NH emissions can be partially attributed to the decrease in N production by a proposed NH conversion to N mechanism. This mechanism predicts that a decrease in NH conversion to N increases ammoniacal N pH. Both effects increase NH emissions. It is unknown whether the decrease in NH conversion to N is a direct or physical result of the decrease in methanogenesis. Procedures and practices intended to reduce emissions of one pollutant can have an unintended consequence on the emissions of another pollutant. PMID:23099928

Weaver, Kim H; Harper, Lowry A; Brown, Sarah M

2012-01-01

138

Biofuel production from catalytic cracking of woody oils.  

PubMed

The catalytic cracking reactions of several kinds of woody oils have been studied. The products were analyzed by GC-MS and FTIR and show the formation of olefins, paraffins and carboxylic acids. Several kinds of catalysts were compared. It was found that the fraction distribution of product was modified by using base catalysts such as CaO. The products from woody oils showed good cold flow properties compared with diesel used in China. The results presented in this work have shown that the catalytic cracking of woody oils generates fuels that have physical and chemical properties comparable to those specified for petroleum based fuels. PMID:20206508

Xu, Junming; Jiang, Jianchun; Chen, Jie; Sun, Yunjuan

2010-07-01

139

Regional Environmental Impacts of Biofuel Feedstock Production--Scaling Biogeochemical Cycles in Space and Time  

NASA Astrophysics Data System (ADS)

Recently there has been increasing socio-economic and scientific interest in the use of alternative sources of energy to offset the negative effects of current fossil fuel dependence and consequent greenhouse gas emissions. Currently, one of the most popular alternatives is to use ethanol produced from domestically grown crops for use as fuel in the transportation sector. In 2007, over 7.5 billion gallons of ethanol were produced in the U.S. from corn, a traditional food crop. Recent research indicates that it may be logistically impractical, ecologically counterproductive (i.e. a net carbon source), and economically devastating to produce ethanol from crops previously grown to produce food. The EBI (Energy Biosciences Institute, at University of California Berkley and University of Illinois Urbana-Champaign) is now conducting research to assess the ability of traditional crops as well as dedicated biofuel feedstocks (e.g. Panicum virgatum (switchgrass), Miscanthus x Giganteus (Miscanthus), and Saccharum spp (sugar cane)) to provide a productive and sustainable alternative to fossil fuel. This is an important step to take before implementing the large-scale growth necessary to meet U.S. energy needs .A process-based terrestrial ecosystem model, Agro-IBIS (Agricultural Integrated Biosphere Simulator) was adapted to simulate the growth of Miscanthus. The model was calibrated using data collected from sites at the University of Illinois south farms. Simulations indicated significant implications on the regional carbon and water budgets. Next this locally validated method will be extrapolated to simulate the regional scale growth of Miscanthus in the Midwestern U.S. and sugarcane in Brazil and a similar analysis will be conducted for switchgrass. The results should provide insight on optimal land-use decisions and legislation that regard meeting energy demands and mitigating climate change in the near future.

Vanloocke, A.; Bernacchi, C.

2008-12-01

140

The benefits of biofuels  

SciTech Connect

This article discusses the economic, environmental, and national security advantages of using biofuels instead of petroleum products in vehicles. Smog and carbon monoxide, two of the most trouble-some urban air pollutants, are largely caused by combustion of conventional petroleum based fuels. Topics include sustainable transportation fuels, emphasis on ethanol, the process of producing biofuels, and the growing market for biofuels. 1 tab.

Hinman, N.D. [National Renewable Energy Lab., Golden, CO (United States)

1997-07-01

141

Production of biofuels from pretreated microalgae biomass by anaerobic fermentation with immobilized Clostridium acetobutylicum cells.  

PubMed

The purpose of this work was to study the possible use of pretreated biomass of various microalgae and cyanobacteria as substrates for acetone-butanol-ethanol (ABE) fermentation by Clostridium acetobutylicum cells immobilized into poly(vinyl alcohol) cryogel. To this end, the biochemical composition of photosynthetic microorganisms cultivated under various conditions was studied. The most efficient technique for pretreating microalgal biomass for its subsequent conversion into biofuels appeared to be thermal decomposition at 108 °C. For the first time the maximum productivity of the ABE fermentation in terms of hydrogen (8.5 mmol/L medium/day) was obtained using pretreated biomass of Nannochloropsis sp. Maximum yields of butanol and ethanol were observed with Arthrospira platensis biomass used as the substrate. Immobilized Clostridium cells were demonstrated to be suitable for multiple reuses (for a minimum of five cycles) in ABE fermentation for producing biofuels from pretreated microalgal biomass. PMID:22483558

Efremenko, E N; Nikolskaya, A B; Lyagin, I V; Senko, O V; Makhlis, T A; Stepanov, N A; Maslova, O V; Mamedova, F; Varfolomeev, S D

2012-06-01

142

Rotating algal biofilm reactor and spool harvester for wastewater treatment with biofuels by-products.  

PubMed

Maximizing algae production in a wastewater treatment process can aid in the reduction of soluble nitrogen and phosphorus concentrations in the wastewater. If harvested, the algae-based biomass offers the added benefit as feedstock for the production of biofuels and bioproducts. However, difficulties in harvesting, concentrating, and dewatering the algae-based biomass have limited the development of an economically feasible treatment and production process. When algae-based biomass is grown as a surface attached biofilm as opposed to a suspended culture, the biomass is naturally concentrated and more easily harvested. This can lead to less expensive removal of the biomass from wastewater, and less expensive downstream processing in the production of biofuels and bioproducts. In this study, a novel rotating algal biofilm reactor (RABR) was designed, built, and tested at bench (8 L), medium (535 L), and pilot (8,000 L) scales. The RABR was designed to operate in the photoautotrophic conditions of open tertiary wastewater treatment, producing mixed culture biofilms made up of algae and bacteria. Growth substrata were evaluated for attachment and biofilm formation, and an effective substratum was discovered. The RABR achieved effective nutrient reduction, with average removal rates of 2.1 and 14.1 g m(-2) day(-1) for total dissolved phosphorus and total dissolved nitrogen, respectively. Biomass production ranged from 5.5 g m(-2) day(-1) at bench scale to as high as 31 g m(-2) day(-1) at pilot scale. An efficient spool harvesting technique was also developed at bench and medium scales to obtain a concentrated product (12-16% solids) suitable for further processing in the production of biofuels and bioproducts. PMID:22328283

Christenson, Logan B; Sims, Ronald C

2012-07-01

143

Biofuels adoption in Nigeria : A preliminary review of feedstock and fuel production potentials  

Microsoft Academic Search

Purpose – The purpose of this paper is to make a preliminary analysis of the potentials for the adoption of biofuels in Nigeria. This initial analysis aims to capture some of the possibilities in the adoption of biofuel and the promotion of the cultivation of energy crops and processing of biofuels in Nigeria. Taking a step towards biofuel adoption is

Nelson Abila

2010-01-01

144

Microalgae-based biorefinery--from biofuels to natural products.  

PubMed

The potential for biodiesel production from microalgal lipids and for CO2 mitigation due to photoautotrophic growth of microalgae have recently been recognized. Microalgae biomass also has other valuable components, including carbohydrates, long chain fatty acids, pigments and proteins. The microalgae-based carbohydrates consist mainly of cellulose and starch without lignin; thus they can be ready carbon source for the fermentation industry. Some microalgae can produce long chain fatty acids (such as DHA and EPA) as valuable health food supplements. In addition, microalgal pigments and proteins have considerable potential for many medical applications. This review article presents comprehensive information on the current state of these commercial applications, as well as the utilization and characteristics of the microalgal components, in addition to the key factors and challenges that should be addressed during the production of these materials, and thus provides a useful report that can aid the development of an efficient microalgae-based biorefinery process. PMID:23206809

Yen, Hong-Wei; Hu, I-Chen; Chen, Chun-Yen; Ho, Shih-Hsin; Lee, Duu-Jong; Chang, Jo-Shu

2013-05-01

145

Bio-Fuel Production Assisted with High Temperature Steam Electrolysis  

SciTech Connect

Two hybrid energy processes that enable production of synthetic liquid fuels that are compatible with the existing conventional liquid transportation fuels infrastructure are presented. Using biomass as a renewable carbon source, and supplemental hydrogen from high-temperature steam electrolysis (HTSE), these two hybrid energy processes have the potential to provide a significant alternative petroleum source that could reduce dependence on imported oil. The first process discusses a hydropyrolysis unit with hydrogen addition from HTSE. Non-food biomass is pyrolyzed and converted to pyrolysis oil. The pyrolysis oil is upgraded with hydrogen addition from HTSE. This addition of hydrogen deoxygenates the pyrolysis oil and increases the pH to a tolerable level for transportation. The final product is synthetic crude that could then be transported to a refinery and input into the already used transportation fuel infrastructure. The second process discusses a process named Bio-Syntrolysis. The Bio-Syntrolysis process combines hydrogen from HTSE with CO from an oxygen-blown biomass gasifier that yields syngas to be used as a feedstock for synthesis of liquid synthetic crude. Conversion of syngas to liquid synthetic crude, using a biomass-based carbon source, expands the application of renewable energy beyond the grid to include transportation fuels. It can also contribute to grid stability associated with non-dispatchable power generation. The use of supplemental hydrogen from HTSE enables greater than 90% utilization of the biomass carbon content which is about 2.5 times higher than carbon utilization associated with traditional cellulosic ethanol production. If the electrical power source needed for HTSE is based on nuclear or renewable energy, the process is carbon neutral. INL has demonstrated improved biomass processing prior to gasification. Recyclable biomass in the form of crop residue or energy crops would serve as the feedstock for this process. A process model of syngas production using high temperature electrolysis and biomass gasification is presented. Process heat from the biomass gasifier is used to heat steam for the hydrogen production via the high temperature steam electrolysis process. Oxygen produced form the electrolysis process is used to control the oxidation rate in the oxygen-blown biomass gasifier.

Grant Hawkes; James O'Brien; Michael McKellar

2012-06-01

146

Green chemistry, biofuels, and biorefinery.  

PubMed

In the current climate of several interrelated impending global crises, namely, climate change, chemicals, energy, and oil, the impact of green chemistry with respect to chemicals and biofuels generated from within a holistic concept of a biorefinery is discussed. Green chemistry provides unique opportunities for innovation via product substitution, new feedstock generation, catalysis in aqueous media, utilization of microwaves, and scope for alternative or natural solvents. The potential of utilizing waste as a new resource and the development of integrated facilities producing multiple products from biomass is discussed under the guise of biorefineries. Biofuels are discussed in depth, as they not only provide fuel (energy) but are also a source of feedstock chemicals. In the future, the commercial success of biofuels commensurate with consumer demand will depend on the availability of new green (bio)chemical technologies capable of converting waste biomass to fuel in a context of a biorefinery. PMID:22468603

Clark, James H; Luque, Rafael; Matharu, Avtar S

2012-01-01

147

De Novo Transcriptomic Analysis of an Oleaginous Microalga: Pathway Description and Gene Discovery for Production of Next-Generation Biofuels  

Microsoft Academic Search

BackgroundEustigmatos cf. polyphem is a yellow-green unicellular soil microalga belonging to the eustimatophyte with high biomass and considerable production of triacylglycerols (TAGs) for biofuels, which is thus referred to as an oleaginous microalga. The paucity of microalgae genome sequences, however, limits development of gene-based biofuel feedstock optimization studies. Here we describe the sequencing and de novo transcriptome assembly for a

LingLin Wan; Juan Han; Min Sang; AiFen Li; Hong Wu; ShunJi Yin; ChengWu Zhang

2012-01-01

148

Projections of Biofuel Growth Patterns Reveal the Potential Importance of Nitrogen Fixation for Miscanthus Productivity  

NASA Astrophysics Data System (ADS)

Demand for liquid biofuels is increasing because of the disparity between fuel demand and supply. Relative to grain crops, the more intensive harvest required for second generation liquid biofuel production leads to the removal of significantly more carbon and nitrogen from the soil. These elements are conventionally litter products of crops that are returned to the soil and can accumulate over time. This loss of organic matter represents a management challenge because the energy cost associated with fertilizers or external sources of organic matter reduce the net energy value of the biofuel crops. Plants that have exceptional strategies for exploiting nutrients may be the most viable options for sustainable biofuel yields because of low management and energy cost. Miscanthus x giganteus has high N retranslocation rates, maintains high photosynthetic rates over a large temperature range, exploits a longer-than-average growing season, and yields at least twice the biomass of other candidate biofuel grass crops (i.e. switchgrass). We employed the DAYCENT model to project potential productivity of Miscanthus, corn, switchgrass, and mixed prairie communities based on our current knowledge of these species. Ecosystem process descriptions that have been validated for many crop species did not accurately predict Miscanthus yields and lead to new hypotheses about unknown N cycling mechanisms for this species. We tested the hypothesis that Miscanthus hosts N-fixing bacteria in several ways. First, we used enrichment culture and molecular methods to detect N-fixing bacteria in Miscanthus. Then, we demonstrated the plant-growth promoting effect of diazotrophs isolated from Miscanthus rhizomes on a model grass. And finally, we applied 15N2 to the soil and rooting zone of field grown Miscanthus plants to determine if atmospheric N2 was incorporated into plant tissue, a process that requires N-fixation. These experiments are the first tests of N-fixation in Miscanthus x giganteus, and the ecosystem model allowed us to project how much nitrogen may be obtained from N-fixation to support sustainable high biomass yields.

Davis, S. C.; Parton, W. J.; Dohleman, F. G.; Gottel, N. R.; Smith, C. M.; Kent, A. D.; Delucia, E. H.

2008-12-01

149

Biofuels from microbes.  

PubMed

Today, biomass covers about 10% of the world's primary energy demand. Against a backdrop of rising crude oil prices, depletion of resources, political instability in producing countries and environmental challenges, besides efficiency and intelligent use, only biomass has the potential to replace the supply of an energy hungry civilisation. Plant biomass is an abundant and renewable source of energy-rich carbohydrates which can be efficiently converted by microbes into biofuels, of which, only bioethanol is produced on an industrial scale today. Biomethane is produced on a large scale, but is not yet utilised for transportation. Biobutanol is on the agenda of several companies and may be used in the near future as a supplement for gasoline, diesel and kerosene, as well as contributing to the partially biological production of butyl-t-butylether, BTBE as does bioethanol today with ETBE. Biohydrogen, biomethanol and microbially made biodiesel still require further development. This paper reviews microbially made biofuels which have potential to replace our present day fuels, either alone, by blending, or by chemical conversion. It also summarises the history of biofuels and provides insight into the actual production in various countries, reviewing their policies and adaptivity to the energy challenges of foreseeable future. PMID:17891391

Antoni, Dominik; Zverlov, Vladimir V; Schwarz, Wolfgang H

2007-11-01

150

Catalytic Fast Pyrolysis for the Production of the Hydrocarbon Biofuels  

SciTech Connect

Catalytic fast pyrolysis is a promising technique for conversion of biomass into hydrocarbons for use as transportation fuels. For over 30 years this process has been studied and it has been demonstrated that oils can be produced with high concentrations of hydrocarbons and low levels of oxygen. However, the yields from this type of conversion are typically low and the catalysts, which are often zeolites, are quickly deactivated through coking. In addition, the hydrocarbons produced are primarily aromatic molecules (benzene, toluene, xylene) that not desirable for petroleum refineries and are not well suited for diesel or jet engines. The goals of our research are to develop new multifunction catalysts for the production of gasoline, diesel and jet fuel range molecules and to improve process conditions for higher yields and low coking rates. We are investigating filtration and the use of hydrogen donor molecules to improve catalyst performance.

Nimlos, M. R.; Robichaud, D. J.; Mukaratate, C.; Donohoe, B. S.; Iisa, K.

2013-01-01

151

Understanding and engineering enzymes for enhanced biofuel production.  

SciTech Connect

Today, carbon-rich fossil fuels, primarily oil, coal and natural gas, provide 85% of the energy consumed in the United States. The release of greenhouse gases from these fuels has spurred research into alternative, non-fossil energy sources. Lignocellulosic biomass is renewable resource that is carbon-neutral, and can provide a raw material for alternative transportation fuels. Plant-derived biomass contains cellulose, which is difficult to convert to monomeric sugars for production of fuels. The development of cost-effective and energy-efficient processes to transform the cellulosic content of biomass into fuels is hampered by significant roadblocks, including the lack of specifically developed energy crops, the difficulty in separating biomass components, the high costs of enzymatic deconstruction of biomass, and the inhibitory effect of fuels and processing byproducts on organisms responsible for producing fuels from biomass monomers. One of the main impediments to more widespread utilization of this important resource is the recalcitrance of cellulosic biomass and techniques that can be utilized to deconstruct cellulosic biomass.

Simmons, Blake Alexander; Volponi, Joanne V.; Sapra, Rajat; Faulon, Jean-Loup Michel; Buffleben, George M.; Roe, Diana C.

2009-01-01

152

Perennial grass production for biofuels: Soil conversion considerations  

SciTech Connect

The increased use of renewable fuels for energy offers the United States a mechanism for significantly reducing national dependency on imported oil, reducing greenhouse gas emissions, and improving regional agricultural economies. As mandated by law, a wide range of issues have been raised regarding the net environmental impacts of implementation of these new technologies. While uncertainties regarding both positive and negative environmental influences still exist in many areas of this new technology, it is now possible to address with substantial certainty the positive aspects of perennial herbaceous energy crops on several important soil conservation issues. Past experience with forage grasses and recent research with switchgrass. A warm season perennial forage grass selected as one of the model bioenergy species, indicates that important benefits will be gained in the area of soil conservation as grasses replace energy-intensive annual row crops. These include reduced erosion, improved conservation of water and nutrients, and increased productivity of soils by the deep and vigorous rooting systems of perennial warm-season gasses.

McLaughlin, S.B. [Oak Ridge National Lab., TN (United States); Bransby, D.I. [Auburn Univ., AL (United States). Dept. of Agronomy and Soils; Parrish, D. [Virginia Polytechnic Institute and State Univ., Blacksburg, VA (United States). Dept. of Crop, Soil, and Environmental Sciences

1994-10-01

153

Sustainability of soil fertility and the use of lignocellulosic crop harvest residues for the production of biofuels: a literature review.  

PubMed

Use of lignocellulosic crop harvest residues for liquid or gaseous biofuel production may impact soil quality, long-term soil fertility and the major determinants of the latter, stocks of soil organic carbon and nutrients. When soil organic carbon stocks of mineral cropland soils are to be maintained, there is scope for the removal of lignocellulosic harvest residues in several systems with much reduced tillage or no tillage. The scope for such removal might be increased when suitably treated residues from the conversion of harvest residues into biofuel are returned to cropland soils. For mineral cropland soils under conventional tillage, the scope for the production of liquid biofuels from harvest residues is likely to be less than in the case of no-till systems. When fertility of cropland soils is to be sustainable, nutrients present in suitably treated biofuel production residues have to be returned to these soils. Apparently, the actual return of carbon and nutrients present in residues of biofuel production from crop harvest residues to arable soils currently predominantly concerns the application of digestates of anaerobic digestion. The effects thereof on soil fertility and quality need further clarification. Further clarification about the effects on soil fertility and quality of chars and of co-products of lignocellulosic ethanol production is also needed. PMID:24350430

Reijnders, L

2013-01-01

154

Catalytic processes towards the production of biofuels in a palm oil and oil palm biomass-based biorefinery.  

PubMed

In Malaysia, there has been interest in the utilization of palm oil and oil palm biomass for the production of environmental friendly biofuels. A biorefinery based on palm oil and oil palm biomass for the production of biofuels has been proposed. The catalytic technology plays major role in the different processing stages in a biorefinery for the production of liquid as well as gaseous biofuels. There are number of challenges to find suitable catalytic technology to be used in a typical biorefinery. These challenges include (1) economic barriers, (2) catalysts that facilitate highly selective conversion of substrate to desired products and (3) the issues related to design, operation and control of catalytic reactor. Therefore, the catalytic technology is one of the critical factors that control the successful operation of biorefinery. There are number of catalytic processes in a biorefinery which convert the renewable feedstocks into the desired biofuels. These include biodiesel production from palm oil, catalytic cracking of palm oil for the production of biofuels, the production of hydrogen as well as syngas from biomass gasification, Fischer-Tropsch synthesis (FTS) for the conversion of syngas into liquid fuels and upgrading of liquid/gas fuels obtained from liquefaction/pyrolysis of biomass. The selection of catalysts for these processes is essential in determining the product distribution (olefins, paraffins and oxygenated products). The integration of catalytic technology with compatible separation processes is a key challenge for biorefinery operation from the economic point of view. This paper focuses on different types of catalysts and their role in the catalytic processes for the production of biofuels in a typical palm oil and oil palm biomass-based biorefinery. PMID:18434141

Chew, Thiam Leng; Bhatia, Subhash

2008-11-01

155

Trace Gas Emissions From the Production and Use of Biofuels in the African Tropics  

NASA Astrophysics Data System (ADS)

Biomass burning is an important source of many atmospheric trace gases and particles that play a significant role in regional-global, tropospheric and stratospheric chemical processes, and in the global climate. About 80% of biomass burning is thought to occur in the tropics in association with traditional land management practices and domestic biofuel use. More than 220 Tg (1 Tg = 1 x 1012 g) of fuel-wood and 11 Tg of charcoal are consumed annually for domestic heating and cooking in tropical Africa alone. Approximately 90% of the fuel-wood is consumed in open fires in rural areas. Previously, the emissions for fuel-wood fires and charcoal use and production in the tropics were known for only a limited number of chemical species. During SAFARI-2000 we conducted field experiments in remote Zambian villages and observed most of the major trace gases emitted from the production and use of biofuels using open-path Fourier transform infrared (OP-FTIR) spectroscopy, which provides an artifact-free overview of the trace gases present above several ppbv. Our OP-FTIR was deployed for several spot measurements over the course of an earthen kiln charcoal-making process and of several open wood and charcoal fires, all of which were built and tended by local inhabitants. We quantified the emissions of carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), nitrogen oxides (NOx), ammonia (NH3), non-methane hydrocarbons (NMHC), and oxygenated volatile organic compounds (OVOC). Our results also show much higher emission factors for methanol (CH3OH), acetic acid (CH3COOH), and formaldehyde (CH2O) from domestic biofuel production and use than from savanna fires in southern Africa. Thus, these year-round OVOC emissions will play an important role in the photochemistry of the troposphere and in the acidity of aerosols and precipitation especially in tropical regions.

Bertschi, I.; Yokelson, R. J.; Ward, D. E.; Christian, T. J.; Hao, W. M.

2001-12-01

156

Microalgal carbohydrates: an overview of the factors influencing carbohydrates production, and of main bioconversion technologies for production of biofuels.  

PubMed

Microalgal biomass seems to be a promising feedstock for biofuel generation. Microalgae have relative high photosynthetic efficiencies, high growth rates, and some species can thrive in brackish water or seawater and wastewater from the food- and agro-industrial sector. Today, the main interest in research is the cultivation of microalgae for lipids production to generate biodiesel. However, there are several other biological or thermochemical conversion technologies, in which microalgal biomass could be used as substrate. However, the high protein content or the low carbohydrate content of the majority of the microalgal species might be a constraint for their possible use in these technologies. Moreover, in the majority of biomass conversion technologies, carbohydrates are the main substrate for production of biofuels. Nevertheless, microalgae biomass composition could be manipulated by several cultivation techniques, such as nutrient starvation or other stressed environmental conditions, which cause the microalgae to accumulate carbohydrates. This paper attempts to give a general overview of techniques that can be used for increasing the microalgal biomass carbohydrate content. In addition, biomass conversion technologies, related to the conversion of carbohydrates into biofuels are discussed. PMID:22996277

Markou, Giorgos; Angelidaki, Irini; Georgakakis, Dimitris

2012-11-01

157

Effects of Escherichia coli on Mixotrophic Growth of Chlorella minutissima and Production of Biofuel Precursors  

PubMed Central

Chlorella minutissima was co-cultured with Escherichia coli in airlift reactors under mixotrophic conditions (glucose, glycerol, and acetate substrates) to determine possible effects of bacterial contamination on algal biofuel production. It was hypothesized that E. coli would compete with C. minutissima for nutrients, displacing algal biomass. However, C. minutissima grew more rapidly and to higher densities in the presence of E. coli, suggesting a symbiotic relationship between the organisms. At an initial 1% substrate concentration, the co-culture produced 200-587% more algal biomass than the axenic C. minutissima cultures. Co-cultures grown on 1% substrate consumed 23–737% more of the available carbon substrate than the sum of substrate consumed by E. coli and C. minutissima alone. At 1% substrate, total lipid and starch productivity were elevated in co-cultures compared to axenic cultures indicating that bacterial contamination was not detrimental to the production of biofuel precursors in this specific case. Bio-fouling of the reactors observed in co-cultures and acid formation in all mixotrophic cultures, however, could present challenges for scale-up.

Higgins, Brendan T.; VanderGheynst, Jean S.

2014-01-01

158

Production of algal-based biofuel using non-fresh water sources.  

SciTech Connect

The goal of this LDRD involves development of a system dynamics model to understand the interdependencies between water resource availability and water needs for production of biofuels. Specifically, this model focuses on availability and feasibility of non-traditional water sources from dairy wastewater, produced water from crude oil production and from coal-bed methane gas extraction for the production of algal-based biofuel. The conceptual simulation framework and historical data are based on two locales within New Mexico, the San Juan basin in the northwest and the Permian basin in the southeast, where oil and gas drilling have increased considerably in the last ten years. The overall water balance ignores both transportation options and water chemistry and is broken down by county level. The resulting model contains an algal growth module, a dairy module, an oil production module, and a gas production module. A user interface is also created for controlling the adjustable parameters in the model. Our preliminary investigation indicates a cyclical demand for non-fresh water due to the cyclical nature of algal biomass production and crop evapotranspiration. The wastewater from the dairy industry is not a feasible non-fresh water source because the agricultural water demand for cow's dry feed far exceeds the amount generated at the dairy. The uncertainty associated with the water demand for cow's dry matter intake is the greatest in this model. The oil- and gas-produced water, ignoring the quality, provides ample supply for water demand in algal biomass production. There remains work to address technical challenges associated with coupling the appropriate non-fresh water source to the local demand.

Sun, Amy Cha-Tien; Reno, Marissa Devan

2007-09-01

159

Comparative genomics of xylose-fermenting fungi for enhanced biofuel production.  

PubMed

Cellulosic biomass is an abundant and underused substrate for biofuel production. The inability of many microbes to metabolize the pentose sugars abundant within hemicellulose creates specific challenges for microbial biofuel production from cellulosic material. Although engineered strains of Saccharomyces cerevisiae can use the pentose xylose, the fermentative capacity pales in comparison with glucose, limiting the economic feasibility of industrial fermentations. To better understand xylose utilization for subsequent microbial engineering, we sequenced the genomes of two xylose-fermenting, beetle-associated fungi, Spathaspora passalidarum and Candida tenuis. To identify genes involved in xylose metabolism, we applied a comparative genomic approach across 14 Ascomycete genomes, mapping phenotypes and genotypes onto the fungal phylogeny, and measured genomic expression across five Hemiascomycete species with different xylose-consumption phenotypes. This approach implicated many genes and processes involved in xylose assimilation. Several of these genes significantly improved xylose utilization when engineered into S. cerevisiae, demonstrating the power of comparative methods in rapidly identifying genes for biomass conversion while reflecting on fungal ecology. PMID:21788494

Wohlbach, Dana J; Kuo, Alan; Sato, Trey K; Potts, Katlyn M; Salamov, Asaf A; Labutti, Kurt M; Sun, Hui; Clum, Alicia; Pangilinan, Jasmyn L; Lindquist, Erika A; Lucas, Susan; Lapidus, Alla; Jin, Mingjie; Gunawan, Christa; Balan, Venkatesh; Dale, Bruce E; Jeffries, Thomas W; Zinkel, Robert; Barry, Kerrie W; Grigoriev, Igor V; Gasch, Audrey P

2011-08-01

160

Comparative genomics of xylose-fermenting fungi for enhanced biofuel production  

PubMed Central

Cellulosic biomass is an abundant and underused substrate for biofuel production. The inability of many microbes to metabolize the pentose sugars abundant within hemicellulose creates specific challenges for microbial biofuel production from cellulosic material. Although engineered strains of Saccharomyces cerevisiae can use the pentose xylose, the fermentative capacity pales in comparison with glucose, limiting the economic feasibility of industrial fermentations. To better understand xylose utilization for subsequent microbial engineering, we sequenced the genomes of two xylose-fermenting, beetle-associated fungi, Spathaspora passalidarum and Candida tenuis. To identify genes involved in xylose metabolism, we applied a comparative genomic approach across 14 Ascomycete genomes, mapping phenotypes and genotypes onto the fungal phylogeny, and measured genomic expression across five Hemiascomycete species with different xylose-consumption phenotypes. This approach implicated many genes and processes involved in xylose assimilation. Several of these genes significantly improved xylose utilization when engineered into S. cerevisiae, demonstrating the power of comparative methods in rapidly identifying genes for biomass conversion while reflecting on fungal ecology.

Wohlbach, Dana J.; Kuo, Alan; Sato, Trey K.; Potts, Katlyn M.; Salamov, Asaf A.; LaButti, Kurt M.; Sun, Hui; Clum, Alicia; Pangilinan, Jasmyn L.; Lindquist, Erika A.; Lucas, Susan; Lapidus, Alla; Jin, Mingjie; Gunawan, Christa; Balan, Venkatesh; Dale, Bruce E.; Jeffries, Thomas W.; Zinkel, Robert; Barry, Kerrie W.; Grigoriev, Igor V.; Gasch, Audrey P.

2011-01-01

161

Comparative Proteomics Analysis of Engineered Saccharomyces cerevisiae with Enhanced Biofuel Precursor Production  

PubMed Central

The yeast Saccharomyces cerevisiae was metabolically modified for enhanced biofuel precursor production by knocking out genes encoding mitochondrial isocitrate dehydrogenase and over-expression of a heterologous ATP-citrate lyase. A comparative iTRAQ-coupled 2D LC-MS/MS analysis was performed to obtain a global overview of ubiquitous protein expression changes in S. cerevisiae engineered strains. More than 300 proteins were identified. Among these proteins, 37 were found differentially expressed in engineered strains and they were classified into specific categories based on their enzyme functions. Most of the proteins involved in glycolytic and pyruvate branch-point pathways were found to be up-regulated and the proteins involved in respiration and glyoxylate pathway were however found to be down-regulated in engineered strains. Moreover, the metabolic modification of S. cerevisiae cells resulted in a number of up-regulated proteins involved in stress response and differentially expressed proteins involved in amino acid metabolism and protein biosynthesis pathways. These LC-MS/MS based proteomics analysis results not only offered extensive information in identifying potential protein-protein interactions, signal pathways and ubiquitous cellular changes elicited by the engineered pathways, but also provided a meaningful biological information platform serving further modification of yeast cells for enhanced biofuel production.

Tang, Xiaoling; Feng, Huixing; Zhang, Jianhua; Chen, Wei Ning

2013-01-01

162

Hydrocracking of vacuum gas oil-vegetable oil mixtures for biofuels production.  

PubMed

Hydrocracking of vacuum gas oil (VGO)--vegetable oil mixtures is a prominent process for the production of biofuels. In this work both pre-hydrotreated and non-hydrotreated VGO are assessed whether they are suitable fossil components in a VGO-vegetable oil mixture as feed-stocks to a hydrocracking process. This assessment indicates the necessity of a VGO pre-hydrotreated step prior to hydrocracking the VGO-vegetable oil mixture. Moreover, the comparison of two different mixing ratios suggests that higher vegetable oil content favors hydrocracking product yields and qualities. Three commercial catalysts of different activity are utilized in order to identify a range of products that can be produced via a hydrocracking route. Finally, the effect of temperature on hydrocracking VGO-vegetable oil mixtures is studied in terms of conversion and selectivity to diesel, jet/kerosene and naphtha. PMID:19231171

Bezergianni, Stella; Kalogianni, Aggeliki; Vasalos, Iacovos A

2009-06-01

163

Thermodynamic analysis of lignocellulosic biofuel production via a biochemical process: guiding technology selection and research focus.  

PubMed

The aim of this paper is to present an exergy analysis of bioethanol production process from lignocellulosic feedstock via a biochemical process to asses the overall thermodynamic efficiency and identify the main loss processes. The thermodynamic efficiency of the biochemical process was found to be 35% and the major inefficiencies of this process were identified as: the combustion of lignin for process heat and power production and the simultaneous scarification and co-fermentation process accounting for 67% and 27% of the lost exergy, respectively. These results were also compared with a previous analysis of a thermochemical process for producing biofuel. Despite fundamental differences, the biochemical and thermochemical processes considered here had similar levels of thermodynamic efficiency. Process heat and power production was the major contributor to exergy loss in both of the processes. Unlike the thermochemical process, the overall efficiency of the biochemical process largely depends on how the lignin is utilized. PMID:21036607

Sohel, M Imroz; Jack, Michael W

2011-02-01

164

Improving photosynthesis and metabolic networks for the competitive production of phototroph-derived biofuels.  

PubMed

To improve bioenergy production from photosynthetic microorganisms it is necessary to optimize an extensive network of highly integrated biological processes. Systematic advances in pathway engineering and culture modification have resulted in strains with increased yields of biohydrogen, lipids, and carbohydrates, three bioenergy foci. However, additional improvements in photosynthetic efficiency are necessary to establish a viable system for biofuel production. Advances in optimizing light capture, energy transfer, and carbon fixation are essential, as the efficiencies of these processes are the principal determinants of productivity. However, owing to their regulatory, catalytic, and structural complexities, manipulating these pathways poses considerable challenges. This review covers novel developments in the optimization of photosynthesis, carbon fixation, and metabolic pathways for the synthesis of targeted bioenergy carriers. PMID:22172528

Work, Victoria H; D'Adamo, Sarah; Radakovits, Randor; Jinkerson, Robert E; Posewitz, Matthew C

2012-06-01

165

Small-scale production of straight vegetable oil from rapeseed and its use as biofuel in the Spanish territory  

Microsoft Academic Search

Biofuels nowadays are an important topic of study. The most significant point is the availability of bioethanol or biodiesel and their production from different raw materials. It is already known that large-scale production of first-generation biodiesel cannot be seen as an alternative to fossil fuels due to land requirements, competition with food, increase in fertilizer requirements and pressure on tropical

Baquero Grau; Esteban Bernat; Rius Antoni; Riba Jordi-Roger; Puig Rita

2010-01-01

166

Relative Impacts of Climate and Land Surface Changes on Hydrology in the US Midwest: Implications for Biofuel Production  

NASA Astrophysics Data System (ADS)

There is considerable interest in biofuel production in the US Midwest; however, potential adverse impacts on water resources are a concern. This study explores relationships between hydrologic change and climate and land surface changes, based on long-term (1930s-2010) monitoring datasets of 45 stream gage stations. Sensitivity of streamflow and baseflow to climate was evaluated using an empirical climate elasticity approach and residuals were attributed to land surface changes. Results show significant increases in streamflow (2.1±0.3 mm/yr) in 24% of stations, increases in baseflow (0.7±0.3 mm/yr) in 60% of stations, and in baseflow index (0.2±0.1%/yr) in 44% of stations. Although climate variability and land surface changes contributed equally to streamflow changes, land surface changes contributed about three times more than climate variability to baseflow and seven times more to baseflow index. Watersheds (~50%) with no significant climate change but with significant flow change provide direct evidence that land surface changes in the Midwest, including crop types, tillage, tiling etc, produced significant impacts on hydrologic processes. Limiting analysis to these watersheds shows that ratios of land surface changes to climate variability was a factor of three for streamflow, 4.6 for baseflow, and 13.5 for baseflow index. These changes in flow have generally been accompanied by degradation of water quality. Because past changes in crop types have been dominated by perennial crops to annual (corn and soybeans) crops, reversal to more perennial grasses for second generation biofuels should reduce flow, particularly baseflow in the future, with consequent improvements in water quality.

Xu, X.; Scanlon, B. R.; Schilling, K.

2012-12-01

167

Effects of future urban and biofuel crop expansions on the riverine export of phosphorus to the Laurentian Great Lakes  

USGS Publications Warehouse

Increased phosphorus (P) loadings threaten the health of the world’s largest freshwater resource, the Laurentian Great Lakes (GL). To understand the linkages between land use and P delivery, we coupled two spatially explicit models, the landscape-scale SPARROW P fate and transport watershed model and the Land Transformation Model (LTM) land use change model, to predict future P export from nonpoint and point sources caused by changes in land use. According to LTM predictions over the period 2010–2040, the GL region of the U.S. may experience a doubling of urbanized areas and agricultural areas may increase by 10%, due to biofuel feedstock cultivation. These land use changes are predicted to increase P loadings from the U.S. side of the GL basin by 3.5–9.5%, depending on the Lake watershed and development scenario. The exception is Lake Ontario, where loading is predicted to decrease by 1.8% for one scenario, due to population losses in the drainage area. Overall, urban expansion is estimated to increase P loadings by 3.4%. Agricultural expansion associated with predicted biofuel feedstock cultivation is predicted to increase P loadings by an additional 2.4%. Watersheds that export P most ef?ciently and thus are the most vulnerable to increases in P sources tend to be found along southern Lake Ontario, southeastern Lake Erie, western Lake Michigan, and southwestern Lake Superior where watershed areas are concentrated along the coastline with shorter ?ow paths. In contrast, watersheds with high soil permeabilities, fractions of land underlain by tile drains, and long distances to the GL are less vulnerable.

LaBeau, Meredith B.; Robertson, Dale M.; Mayer, Alex S.; Pijanowski, Bryan C.; Saad, David A.

2013-01-01

168

Water Resources Implications of Cellulosic Biofuel Production at a Regional Scale  

NASA Astrophysics Data System (ADS)

Recent increases in oil prices, a strong national interest in greater energy independence, and a concern for the role of fossil fuels in global climate change, have led to a dramatic expansion in use of alternative renewable energy sources in the U.S. The U.S. government has mandated production of 36 billion gallons of renewable fuels by 2022, of which 16 billion gallons are required to be cellulosic biofuels. Production of cellulosic biomass offers a promising alternative to corn-based systems because large-scale production of corn-based ethanol often requires irrigation and is associated with increased erosion, excess sediment export, and enhanced leaching of nitrogen and phosphorus. Although cultivation of switchgrass using standard agricultural practices is one option being considered for production of cellulosic biomass, intercropping cellulosic biofuel crops within managed forests could provide feedstock without primary land use change or the water quality impacts associated with annual crops. Catchlight Energy LLC is examining the feasibility and sustainability of intercropping switchgrass in loblolly pine plantations in the southeastern U.S. Ongoing research is determining efficient operational techniques and information needed to evaluate effects of these practices on water resources in small watershed-scale (~25 ha) studies. Three sets of four to five sub-watersheds are fully instrumented and currently collecting calibration data in North Carolina, Alabama, and Mississippi. These watershed studies will provide detailed information to understand processes and guide management decisions. However, environmental implications of cellulosic systems need to be examined at a regional scale. We used the Soil Water Assessment Tool (SWAT), a physically-based hydrologic model, to examine water quantity effects of various land use change scenarios ranging from switchgrass intercropping a small percentage of managed pine forest land to conversion of all managed forested land to switchgrass. The regional-scale SWAT model was successfully run and calibrated on the ~ 5 million ha Tombigbee Watershed located in Mississippi and Alabama. Publically available datasets were used as input to the model and for calibration. To improve calibration statistics, five tree age classes (0-4 yr, 4-10 yr, 10-17 yr, 17-24 yr, 24-30 yr) were added to the model to more appropriately represent existing forested systems in the region, which are not included within the standard SWAT set-up. Our results will be essential to public policy makers as they influence and plan for large-scale production of cellulosic biofuels, while sustaining water quality and quantity.

Christopher, S. F.; Schoenholtz, S. H.; Nettles, J. E.

2011-12-01

169

Spatial forecasting of switchgrass productivity under current and future climate change scenarios.  

PubMed

Evaluating the potential of alternative energy crops across large geographic regions, as well as over time, is a necessary component to determining if biofuel production is feasible and sustainable in the face of growing production demands and climatic change. Switchgrass (Panicum virgatum L.), a native perennial herbaceous grass, is a promising candidate for cellulosic feedstock production. In this study, current and future (from 2080 to 2090) productivity is estimated across the central and eastern United States using ALMANAC, a mechanistic model that simulates plant growth over time. The ALMANAC model was parameterized for representative ecotypes of switchgrass. Our results indicate substantial variation in switchgrass productivity both within regions and over time. States along the Gulf Coast, southern Atlantic Coast, and in the East North Central Midwest have the highest current biomass potential. However, these areas also contain critical wetland habitat necessary for the maintenance of biodiversity and agricultural lands necessary for food production. The southern United States is predicted to have the largest decrease in future biomass production. The Great Plains are expected to experience large increases in productivity by 2080-2090 due to climate change. In general, regions where future temperature and precipitation are predicted to increase are also where larger future biomass production is expected. In contrast, regions that show a future decrease in precipitation are associated with smaller future biomass production. Switchgrass appears to be a promising biofuel crop for the central and eastern United States, with local biomass predicted to be high (>10 Mg/ha) for approximately 50% of the area studied for each climate scenario. In order to minimize land conversion and loss of biodiversity, areas that currently have and maintain high productivity under climate change should be targeted for their long-term growth potential. PMID:23495637

Behrman, Kathrine D; Kiniry, James R; Winchell, Michael; Juenger, Thomas E; Keitt, Timothy H

2013-01-01

170

Black liquor fractionation for biofuels production - A techno-economic assessment.  

PubMed

The hemicelluloses fraction of black liquor is an underutilized resource in many chemical pulp mills. It is possible to extract and separate the lignin and hemicelluloses from the black liquor and use the hemicelluloses for biochemical conversion into biofuels and chemicals. Precipitation of the lignin from the black liquor would consequently decrease the thermal load on the recovery boiler, which is often referred to as a bottleneck for increased pulp production. The objective of this work is to techno-economically evaluate the production of sodium-free lignin as a solid fuel and butanol to be used as fossil gasoline replacement by fractionating black liquor. The hydrolysis and fermentation processes are modeled in Aspen Plus to analyze energy and material balances as well as to evaluate the plant economics. A mathematical model of an existing pulp and paper mill is used to analyze the effects on the energy performance of the mill subprocesses. PMID:24950095

Mesfun, Sennai; Lundgren, Joakim; Grip, Carl-Erik; Toffolo, Andrea; Nilsson, Rasika Lasanthi Kudahettige; Rova, Ulrika

2014-08-01

171

A Biophysical Modeling Framework for Assessing the Environmental Impact of Biofuel Production  

NASA Astrophysics Data System (ADS)

Long-term sustainability of a biofuel economy necessitates environmentally friendly biofuel production systems. We describe a biophysical modeling framework developed to understand and quantify the environmental value and impact (e.g. water balance, nutrients balance, carbon balance, and soil quality) of different biomass cropping systems. This modeling framework consists of three major components: 1) a Geographic Information System (GIS) based data processing system, 2) a spatially-explicit biophysical modeling approach, and 3) a user friendly information distribution system. First, we developed a GIS to manage the large amount of geospatial data (e.g. climate, land use, soil, and hydrograhy) and extract input information for the biophysical model. Second, the Environmental Policy Integrated Climate (EPIC) biophysical model is used to predict the impact of various cropping systems and management intensities on productivity, water balance, and biogeochemical variables. Finally, a geo-database is developed to distribute the results of ecosystem service variables (e.g. net primary productivity, soil carbon balance, soil erosion, nitrogen and phosphorus losses, and N2O fluxes) simulated by EPIC for each spatial modeling unit online using PostgreSQL. We applied this framework in a Regional Intensive Management Area (RIMA) of 9 counties in Michigan. A total of 4,833 spatial units with relatively homogeneous biophysical properties were derived using SSURGO, Crop Data Layer, County, and 10-digit watershed boundaries. For each unit, EPIC was executed from 1980 to 2003 under 54 cropping scenarios (eg. corn, switchgrass, and hybrid poplar). The simulation results were compared with historical crop yields from USDA NASS. Spatial mapping of the results show high variability among different cropping scenarios in terms of the simulated ecosystem services variables. Overall, the framework developed in this study enables the incorporation of environmental factors into economic and life-cycle analysis in order to optimize biomass cropping production scenarios.

Zhang, X.; Izaurradle, C.; Manowitz, D.; West, T. O.; Post, W. M.; Thomson, A. M.; Nichols, J.; Bandaru, V.; Williams, J. R.

2009-12-01

172

The future of patent information products  

Microsoft Academic Search

The article discusses the online patent information products available at present and describes the information products which are about to be produced by the EPO or are planned for the near future. The latter include mixed mode products covering numerical and classified files on mainframe or CD-ROM. The problems of storage of 25 million documents and improvements necessary in workstations

J. Michel

1991-01-01

173

Mitigation: A sweetener for biofuels  

NASA Astrophysics Data System (ADS)

The climate impact of biofuels is usually considered in terms of their net effect on greenhouse-gas emissions. The expansion of sugar cane into pastureland for biofuel production is now shown to also exert a direct local cooling effect.

Betts, Richard A.

2011-05-01

174

Gaining ground in the modeling of land-use change greenhouse gas emissions associated with biofuel production  

NASA Astrophysics Data System (ADS)

Land-use change (LUC) resulting from biofuel feedstock production and the associated greenhouse gas (GHG) emissions are a hotly-debated aspect of biofuels. Certainly, LUC GHG emissions are one of the most uncertain elements in life cycle analyses (LCA) of biofuels. To estimate LUC GHG emissions, two sets of data are necessary. First, information on the amount and type of land that is converted to biofuel feedstock production is required. These data are typically generated through application of computable general equilibrium (CGE) models such as Purdue University's Global Trade Analysis Project (GTAP) model. Second, soil carbon content data for the affected land types is essential. Recently, Argonne National Laboratory's Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) has been updated with CGE modeling results that estimate the amount and type of LUC world-wide from production of ethanol from corn, corn stover, miscanthus, and switchgrass (Mueller et al. 2012). Moreover, we have developed state-specific carbon content data, determined through modeling with CENTURY, for the two most dominant soil types in the conterminous 48 U.S. states (Kwon et al. 2012) to enable finer-resolution results for domestic LUC GHG emissions for these ethanol production scenarios. Of the feedstocks examined, CCLUB estimates that LUC GHG emissions are highest for corn ethanol (9.1 g CO2e/MJ ethanol) and lowest for miscanthus (-12 g CO2e/MJ ethanol). We will present key observations from CCLUB results incorporated into Argonne National Laboratory's Greenhouse Gases, Regulated Emissions, and Energy use in Transportation (GREET) model, which is a LCA tool for transportation fuels and advanced vehicle technologies. We will discuss selected issues in this modeling, including the sensitivity of domestic soil carbon emission factors to modeling parameters and assumptions about the fate of harvested wood products. Further, we will discuss efforts to update CCLUB with county-level soil carbon emission factors and updated international soil carbon emission factors. Finally, we will examine data needs for improved LUC GHG calculations in both the modeling of land conversion and soil carbon content. Kwon, H. Y., Wander, M. M., Mueller, S., Dunn, J. B. "Modeling state-level soil carbon emission factors under various scenarios for direct land use change associated with United States biofuel feedstock production." Biomass and Bioenergy. Under Review. Mueller, S., Dunn, J. B., Wang, M. "Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) Users' Manual and Technical Documentation." May 2012. ANL/ESD/12-5. Available at http://greet.es.anl.gov/publication-cclub-manual.

Dunn, J.; Mueller, S.; Kwon, H.; Wang, M.; Wander, M.

2012-12-01

175

Production of Algal-based Biofuel from Non-fresh Water Sources  

NASA Astrophysics Data System (ADS)

A system dynamics model is developed to assess the availability and feasibility of non-traditional water sources from dairy wastewater, produced water from crude oil production and from coal-bed methane gas extraction for the production of algal-based biofuel. The conceptual framework is based on two locales within New Mexico, the San Juan basin in the northwest and the Permian basin in the southeast, where oil and gas drilling have increased considerably in the last ten years. The simulation framework contains an algal growth module, a dairy module, an oil production module, and a gas production module. Our preliminary investigation indicates a cyclical demand for non-fresh water due to the cyclical nature of algal biomass production and crop evapotranspiration. The wastewater from the dairy industry is not a feasible non-fresh water source because the agricultural water demand for cow's dry feed far exceeds the amount generated at the dairy. The uncertainty associated with the water demand for cow's dry matter intake is the greatest in this model. The oil and gas produced water, ignoring the quality, provides ample supply for water demand in algal biomass production. There remains work to address technical challenges associated with coupling the appropriate non-fresh water source to the local demand.

Sun, A. C.; Reno, M. D.

2008-12-01

176

Educare: new product, new future.  

PubMed

On September 2, 1990, something very informative about the evolution of early childhood programs in the minds of people appeared in The New York Times. Perhaps only another historian of trivia would have noticed it, but it was significant. The Sunday crossword puzzle had the following cue for 4 down: "Places for day-care" (spelled, with the purist's uncertainty, with a hyphen). Even such a cautious horizontal-vertical weaver as I am did not have to wait very long before filling in the correct 10 letters: "preschools." Preschools = day-cares; day-cares = preschools. I am told that actors and authors and scientists know that they have it made when their names are required as solutions in a Times crossword puzzle. If so, perhaps we now have tangible proof that those of us have at last been heard who have urged acceptance of the concept that early childhood education (or preschool education) and child care (or day care) are really one and the same essential service operated for different lengths of time. Day care, the illegitimate child of the scientific field that gave birth to the early childhood movement, has turned out to be the only offspring sufficiently well endowed and robust to make it in the modern world. It is the only one possessing the characteristics that will enable it to take the family enterprise into the future. At this juncture, near the close of the century during which programs for young children multiplied to the point where they cannot be ignored as significant factors in family and public life, we are on the threshold of a new era.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1869626

Caldwell, B

1991-06-01

177

Catalytic cracking of palm oil for the production of biofuels: optimization studies.  

PubMed

Oil palm is widely grown in Malaysia. Palm oil has attracted the attention of researchers to develop an 'environmentally friendly' and high quality fuel, free of nitrogen and sulfur. In the present study, the catalytic cracking of palm oil to biofuel was studied over REY catalyst in a transport riser reactor at atmospheric pressure. The effect of reaction temperature (400-500 degrees C), catalyst/palm oil ratio (5-10) and residence time (10-30s) was studied over the yield of bio-gasoline and gas as fuel. Design of experiments was used to study the effect of operating variables over conversion of palm oil and yield of hydrocarbon fuel. The response surface methodology was used to determine the optimum value of the operating variables for maximum yield of bio-gasoline fraction in the liquid product obtained. PMID:17208441

Tamunaidu, Pramila; Bhatia, Subhash

2007-12-01

178

The role of symbiotic nitrogen fixation in sustainable production of biofuels.  

PubMed

With the ever-increasing population of the world (expected to reach 9.6 billion by 2050), and altered life style, comes an increased demand for food, fuel and fiber. However, scarcity of land, water and energy accompanied by climate change means that to produce enough to meet the demands is getting increasingly challenging. Today we must use every avenue from science and technology available to address these challenges. The natural process of symbiotic nitrogen fixation, whereby plants such as legumes fix atmospheric nitrogen gas to ammonia, usable by plants can have a substantial impact as it is found in nature, has low environmental and economic costs and is broadly established. Here we look at the importance of symbiotic nitrogen fixation in the production of biofuel feedstocks; how this process can address major challenges, how improving nitrogen fixation is essential, and what we can do about it. PMID:24786096

Biswas, Bandana; Gresshoff, Peter M

2014-01-01

179

The Role of Symbiotic Nitrogen Fixation in Sustainable Production of Biofuels  

PubMed Central

With the ever-increasing population of the world (expected to reach 9.6 billion by 2050), and altered life style, comes an increased demand for food, fuel and fiber. However, scarcity of land, water and energy accompanied by climate change means that to produce enough to meet the demands is getting increasingly challenging. Today we must use every avenue from science and technology available to address these challenges. The natural process of symbiotic nitrogen fixation, whereby plants such as legumes fix atmospheric nitrogen gas to ammonia, usable by plants can have a substantial impact as it is found in nature, has low environmental and economic costs and is broadly established. Here we look at the importance of symbiotic nitrogen fixation in the production of biofuel feedstocks; how this process can address major challenges, how improving nitrogen fixation is essential, and what we can do about it.

Biswas, Bandana; Gresshoff, Peter M.

2014-01-01

180

An engineered microbial platform for direct biofuel production from brown macroalgae.  

PubMed

Prospecting macroalgae (seaweeds) as feedstocks for bioconversion into biofuels and commodity chemical compounds is limited primarily by the availability of tractable microorganisms that can metabolize alginate polysaccharides. Here, we present the discovery of a 36-kilo-base pair DNA fragment from Vibrio splendidus encoding enzymes for alginate transport and metabolism. The genomic integration of this ensemble, together with an engineered system for extracellular alginate depolymerization, generated a microbial platform that can simultaneously degrade, uptake, and metabolize alginate. When further engineered for ethanol synthesis, this platform enables bioethanol production directly from macroalgae via a consolidated process, achieving a titer of 4.7% volume/volume and a yield of 0.281 weight ethanol/weight dry macroalgae (equivalent to ~80% of the maximum theoretical yield from the sugar composition in macroalgae). PMID:22267807

Wargacki, Adam J; Leonard, Effendi; Win, Maung Nyan; Regitsky, Drew D; Santos, Christine Nicole S; Kim, Peter B; Cooper, Susan R; Raisner, Ryan M; Herman, Asael; Sivitz, Alicia B; Lakshmanaswamy, Arun; Kashiyama, Yuki; Baker, David; Yoshikuni, Yasuo

2012-01-20

181

Trash to treasure: production of biofuels and commodity chemicals via syngas fermenting microorganisms.  

PubMed

Fermentation of syngas is a means through which unutilized organic waste streams can be converted biologically into biofuels and commodity chemicals. Despite recent advances, several issues remain which limit implementation of industrial-scale syngas fermentation processes. At the cellular level, the energy conservation mechanism of syngas fermenting microorganisms has not yet been entirely elucidated. Furthermore, there was a lack of genetic tools to study and ultimately enhance their metabolic capabilities. Recently, substantial progress has been made in understanding the intricate energy conservation mechanisms of these microorganisms. Given the complex relationship between energy conservation and metabolism, strain design greatly benefits from systems-level approaches. Numerous genetic manipulation tools have also been developed, paving the way for the use of metabolic engineering and systems biology approaches. Rational strain designs can now be deployed resulting in desirable phenotypic traits for large-scale production. PMID:24863900

Latif, Haythem; Zeidan, Ahmad A; Nielsen, Alex T; Zengler, Karsten

2014-06-01

182

Metabolic and cellular organization in evolutionarily diverse microalgae as related to biofuels production.  

PubMed

Microalgae are among the most diverse organisms on the planet, and as a result of symbioses and evolutionary selection, the configuration of core metabolic networks is highly varied across distinct algal classes. The differences in photosynthesis, carbon fixation and processing, carbon storage, and the compartmentation of cellular and metabolic processes are substantial and likely to transcend into the efficiency of various steps involved in biofuel molecule production. By highlighting these differences, we hope to provide a framework for comparative analyses to determine the efficiency of the different arrangements or processes. This sets the stage for optimization on the based on information derived from evolutionary selection to diverse algal classes and to synthetic systems. PMID:23538202

Hildebrand, Mark; Abbriano, Raffaela M; Polle, Juergen E W; Traller, Jesse C; Trentacoste, Emily M; Smith, Sarah R; Davis, Aubrey K

2013-06-01

183

Genome replication engineering assisted continuous evolution (GREACE) to improve microbial tolerance for biofuels production  

PubMed Central

Background Microbial production of biofuels requires robust cell growth and metabolism under tough conditions. Conventionally, such tolerance phenotypes were engineered through evolutionary engineering using the principle of “Mutagenesis followed-by Selection”. The iterative rounds of mutagenesis-selection and frequent manual interventions resulted in discontinuous and inefficient strain improvement processes. This work aimed to develop a more continuous and efficient evolutionary engineering method termed as “Genome Replication Engineering Assisted Continuous Evolution” (GREACE) using “Mutagenesis coupled-with Selection” as its core principle. Results The core design of GREACE is to introduce an in vivo continuous mutagenesis mechanism into microbial cells by introducing a group of genetically modified proofreading elements of the DNA polymerase complex to accelerate the evolution process under stressful conditions. The genotype stability and phenotype heritability can be stably maintained once the genetically modified proofreading element is removed, thus scarless mutants with desired phenotypes can be obtained. Kanamycin resistance of E. coli was rapidly improved to confirm the concept and feasibility of GREACE. Intrinsic mechanism analysis revealed that during the continuous evolution process, the accumulation of genetically modified proofreading elements with mutator activities endowed the host cells with enhanced adaptation advantages. We further showed that GREACE can also be applied to engineer n-butanol and acetate tolerances. In less than a month, an E. coli strain capable of growing under an n-butanol concentration of 1.25% was isolated. As for acetate tolerance, cell growth of the evolved E. coli strain increased by 8-fold under 0.1% of acetate. In addition, we discovered that adaptation to specific stresses prefers accumulation of genetically modified elements with specific mutator strengths. Conclusions We developed a novel GREACE method using “Mutagenesis coupled-with Selection” as core principle. Successful isolation of E. coli strains with improved n-butanol and acetate tolerances demonstrated the potential of GREACE as a promising method for strain improvement in biofuels production.

2013-01-01

184

Iron oxide filled magnetic carbon nanotube-enzyme conjugates for recycling of amyloglucosidase: toward useful applications in biofuel production process.  

PubMed

Biofuels are fast advancing as a new research area to provide alternative sources of sustainable and clean energy. Recent advances in nanotechnology have sought to improve the efficiency of biofuel production, enhancing energy security. In this study, we have incorporated iron oxide nanoparticles into single-walled carbon nanotubes (SWCNTs) to produce magnetic single-walled carbon nanotubes (mSWCNTs). Our objective is to bridge both nanotechnology and biofuel production by immobilizing the enzyme, Amyloglucosidase (AMG), onto mSWCNTs using physical adsorption and covalent immobilization, with the aim of recycling the immobilized enzyme, toward useful applications in biofuel production processes. We have demonstrated that the enzyme retains a certain percentage of its catalytic efficiency (up to 40%) in starch prototype biomass hydrolysis when used repeatedly (up to ten cycles) after immobilization on mSWCNTs, since the nanotubes can be easily separated from the reaction mixture using a simple magnet. The enzyme loading, activity, and structural changes after immobilization onto mSWCNTs were also studied. In addition, we have demonstrated that the immobilized enzyme retains its activity when stored at 4 °C for at least one month. These results, combined with the unique intrinsic properties of the nanotubes, pave the way for greater efficiency in carbon nanotube-enzyme bioreactors and reduced capital costs in industrial enzyme systems. PMID:23148719

Goh, Wei Jiang; Makam, Venkata S; Hu, Jun; Kang, Lifeng; Zheng, Minrui; Yoong, Sia Lee; Udalagama, Chammika N B; Pastorin, Giorgia

2012-12-11

185

Present and Future IGS Ionospheric Products  

Microsoft Academic Search

The purpose of this paper is, on one hand, to show the present performance of the combined final and rapid IGS global ionosphere maps (GIMs), and on the other hand to inform the geodetic community on new product - predicted IGS GIMs. In addition, information on future development of IGS ionospheric products will be also presented. Nowadays, the Ionosphere Working

Andrzej Krankowski; Pawel Wielgosz; Manuel Hernández-Pajares; Alberto García-Rigo

2010-01-01

186

Biofuels are dead: long live biofuels(?) - part two.  

PubMed

Whilst obsessing over the policy catastrophe surrounding biofuels, we could easily lose sight of the prospects for science and technology to increase the sustainability of biofuel production by orders of magnitude. Part two of this feature examines the research and development of more sustainable biofuels. PMID:18761111

Moore, Andrew

2008-01-01

187

Metabolic engineering of Saccharomyces cerevisiae for production of fatty acid-derived biofuels and chemicals.  

PubMed

As the serious effects of global climate change become apparent and access to fossil fuels becomes more limited, metabolic engineers and synthetic biologists are looking towards greener sources for transportation fuels. In recent years, microbial production of high-energy fuels by economically efficient bioprocesses has emerged as an attractive alternative to the traditional production of transportation fuels. Here, we engineered the budding yeast Saccharomyces cerevisiae to produce fatty acid-derived biofuels and chemicals from simple sugars. Specifically, we overexpressed all three fatty acid biosynthesis genes, namely acetyl-CoA carboxylase (ACC1), fatty acid synthase 1 (FAS1) and fatty acid synthase 2 (FAS2), in S. cerevisiae. When coupled to triacylglycerol (TAG) production, the engineered strain accumulated lipid to more than 17% of its dry cell weight, a four-fold improvement over the control strain. Understanding that TAG cannot be used directly as fuels, we also engineered S. cerevisiae to produce drop-in fuels and chemicals. Altering the terminal "converting enzyme" in the engineered strain led to the production of free fatty acids at a titer of approximately 400 mg/L, fatty alcohols at approximately 100mg/L and fatty acid ethyl esters (biodiesel) at approximately 5 mg/L directly from simple sugars. We envision that our approach will provide a scalable, controllable and economic route to this important class of chemicals. PMID:23899824

Runguphan, Weerawat; Keasling, Jay D

2014-01-01

188

Addressing the challenges for sustainable production of algal biofuels: I. Algal strains and nutrient supply.  

PubMed

Microalgae hold promise for the production of sustainable replacement of fossil fuels due to their high growth rates, ability to grow on non-arable land and their high content, under the proper conditions, of high energy compounds that can be relatively easily chemically converted to fuels using existing technology. However, projected large-scale algal production raises a number of sustainability concerns concerning land use, net energy return, water use and nutrient supply. The state-of-the-art of algal production of biofuels is presented with emphasis on some possible avenues to provide answers to the sustainability questions that have been raised. Here, issues concerning algal strains and supply of nutrients for large-scale production are discussed. Since sustainability concerns necessitate the use of wastewaters for supply of bulk nutrients, emphasis is placed on the composition and suitability of different wastewater streams. At the same time, algal cultivation has proven useful in waste treatment processes, and thus this aspect is also treated in some detail. PMID:24350435

Abdelaziz, Ahmed E M; Leite, Gustavo B; Hallenbeck, Patrick C

2013-01-01

189

Engineering plastid fatty acid biosynthesis to improve food quality and biofuel production in higher plants.  

PubMed

The ability to manipulate plant fatty acid biosynthesis by using new biotechnological approaches has allowed the production of transgenic plants with unusual fatty acid profile and increased oil content. This review focuses on the production of very long chain polyunsaturated fatty acids (VLCPUFAs) and the increase in oil content in plants using molecular biology tools. Evidences suggest that regular consumption of food rich in VLCPUFAs has multiple positive health benefits. Alternative sources of these nutritional fatty acids are found in cold-water fishes. However, fish stocks are in severe decline because of decades of overfishing, and also fish oils can be contaminated by the accumulation of toxic compounds. Recently, there is also an increase in oilseed use for the production of biofuels. This tendency is partly associated with the rapidly rising costs of petroleum, increased concern about the environmental impact of fossil oil and the attractive need to develop renewable sources of fuel. In contrast to this scenario, oil derived from crop plants is normally contaminant free and less environmentally aggressive. Genetic engineering of the plastid genome (plastome) offers a number of attractive advantages, including high-level foreign protein expression, marker-gene excision and transgene containment because of maternal inheritance of plastid genome in most crops. Here, we describe the possibility to improve fatty acid biosynthesis in plastids, production of new fatty acids and increase their content in plants by genetic engineering of plastid fatty acid biosynthesis via plastid transformation. PMID:21535359

Rogalski, Marcelo; Carrer, Helaine

2011-06-01

190

%22Trojan Horse%22 strategy for deconstruction of biomass for biofuels production.  

SciTech Connect

Production of renewable biofuels to displace fossil fuels currently consumed in the transportation sector is a pressing multiagency national priority (DOE/USDA/EERE). Currently, nearly all fuel ethanol is produced from corn-derived starch. Dedicated 'energy crops' and agricultural waste are preferred long-term solutions for renewable, cheap, and globally available biofuels as they avoid some of the market pressures and secondary greenhouse gas emission challenges currently facing corn ethanol. These sources of lignocellulosic biomass are converted to fermentable sugars using a variety of chemical and thermochemical pretreatments, which disrupt cellulose and lignin cross-links, allowing exogenously added recombinant microbial enzymes to more efficiently hydrolyze the cellulose for 'deconstruction' into glucose. This process is plagued with inefficiencies, primarily due to the recalcitrance of cellulosic biomass, mass transfer issues during deconstruction, and low activity of recombinant deconstruction enzymes. Costs are also high due to the requirement for enzymes and reagents, and energy-intensive cumbersome pretreatment steps. One potential solution to these problems is found in synthetic biology-engineered plants that self-produce a suite of cellulase enzymes. Deconstruction can then be integrated into a one-step process, thereby increasing efficiency (cellulose-cellulase mass-transfer rates) and reducing costs. The unique aspects of our approach are the rationally engineered enzymes which become Trojan horses during pretreatment conditions. During this study we rationally engineered Cazy enzymes and then integrated them into plant cells by multiple transformation techniques. The regenerated plants were assayed for first expression of these messages and then for the resulting proteins. The plants were then subjected to consolidated bioprocessing and characterized in detail. Our results and possible implications of this work on developing dedicated energy crops and their advantage in a consolidated bioprocessing system.

Simmons, Blake Alexander; Sinclair, Michael B.; Yu, Eizadora; Timlin, Jerilyn Ann; Hadi, Masood Z.; Tran-Gyamfi, Mary

2011-02-01

191

The role of biochemical engineering in the production of biofuels from microalgae  

Microsoft Academic Search

Environmental changes that have occurred due to the use of fossil fuels have driven the search for alternative sources that have a lower environmental impact. First-generation biofuels were derived from crops such as sugar cane, corn and soybean, which contribute to water scarcity and deforestation. Second-generation biofuels originated from lignocellulose agriculture and forest residues, however these needed large areas of

Jorge Alberto Vieira Costa; Michele Greque de Morais

2011-01-01

192

A DYNAMIC GENERAL EQUILIBRIUM ANALYSIS OF U.S. BIOFUELS PRODUCTION  

Microsoft Academic Search

With the rising global interest in energy security and climate change mitigation, biofuels have gained the prominent attention of researchers and policy makers. The U.S. has emerged as the leading producer of biofuels and is aiming for achieving a target of 36 billion gallons of renewable fuels by 2022 under its updated renewable fuels standard (RFS2) policy. In this paper,

Robert H. Beach; Dileep K. Birur; Lauren M. Davis; Martin T. Ross

2011-01-01

193

Stimulating learning-by-doing in advanced biofuels: effectiveness of alternative policies  

NASA Astrophysics Data System (ADS)

This letter examines the effectiveness of various biofuel and climate policies in reducing future processing costs of cellulosic biofuels due to learning-by-doing. These policies include a biofuel production mandate alone and supplementing the biofuel mandate with other policies, namely a national low carbon fuel standard, a cellulosic biofuel production tax credit or a carbon price policy. We find that the binding biofuel targets considered here can reduce the unit processing cost of cellulosic ethanol by about 30% to 70% between 2015 and 2035 depending on the assumptions about learning rates and initial costs of biofuel production. The cost in 2035 is more sensitive to the speed with which learning occurs and less sensitive to uncertainty in the initial production cost. With learning rates of 5-10%, cellulosic biofuels will still be at least 40% more expensive than liquid fossil fuels in 2035. The addition of supplementary low carbon/tax credit policies to the mandate that enhance incentives for cellulosic biofuels can achieve similar reductions in these costs several years earlier than the mandate alone; the extent of these incentives differs across policies and different kinds of cellulosic biofuels.

Chen, Xiaoguang; Khanna, Madhu; Yeh, Sonia

2012-12-01

194

Algae as a Feedstock for Transportation Fuels. The Future of Biofuels?  

Microsoft Academic Search

Events in world energy markets over the past several years have prompted many new technical developments as well as political support for alternative transportation fuels, especially those that are renewable. We have seen dramatic rises in the demand for and production of fuel ethanol from sugar cane and corn and biodiesel from vegetable oils. The quantities of these fuels being

McGill; Ralph

2008-01-01

195

Local bioprospecting for high-lipid producing microalgal strains to be grown on concentrated municipal wastewater for biofuel production  

Microsoft Academic Search

Mass cultivation of microalgae for biofuel production depends heavily on the performance of the microalgae strains used. In this study, 60 algae-like microorganisms collected from different sampling sites in Minnesota were examined using multi-step screening and acclimation procedures to select high-lipid producing facultative heterotrophic microalgae strains capable of growing on concentrated municipal wastewater (CMW) for simultaneous energy crop production and

Wenguang Zhou; Yecong Li; Min Min; Bing Hu; Paul Chen; Roger Ruan

2011-01-01

196

Watermelon juice: a promising feedstock supplement, diluent, and nitrogen supplement for ethanol biofuel production  

PubMed Central

Background Two economic factors make watermelon worthy of consideration as a feedstock for ethanol biofuel production. First, about 20% of each annual watermelon crop is left in the field because of surface blemishes or because they are misshapen; currently these are lost to growers as a source of revenue. Second, the neutraceutical value of lycopene and L-citrulline obtained from watermelon is at a threshold whereby watermelon could serve as starting material to extract and manufacture these products. Processing of watermelons to produce lycopene and L-citrulline, yields a waste stream of watermelon juice at the rate of over 500 L/t of watermelons. Since watermelon juice contains 7 to 10% (w/v) directly fermentable sugars and 15 to 35 ?mol/ml of free amino acids, its potential as feedstock, diluent, and nitrogen supplement was investigated in fermentations to produce bioethanol. Results Complete watermelon juice and that which did not contain the chromoplasts (lycopene), but did contain free amino acids, were readily fermentable as the sole feedstock or as diluent, feedstock supplement, and nitrogen supplement to granulated sugar or molasses. A minimum level of ~400 mg N/L (~15 ?mol/ml amino nitrogen) in watermelon juice was required to achieve maximal fermentation rates when it was employed as the sole nitrogen source for the fermentation. Fermentation at pH 5 produced the highest rate of fermentation for the yeast system that was employed. Utilizing watermelon juice as diluent, supplemental feedstock, and nitrogen source for fermentation of processed sugar or molasses allowed complete fermentation of up to 25% (w/v) sugar concentration at pH 3 (0.41 to 0.46 g ethanol per g sugar) or up to 35% (w/v) sugar concentration at pH 5 with a conversion to 0.36 to 0.41 g ethanol per g sugar. Conclusion Although watermelon juice would have to be concentrated 2.5- to 3-fold to serve as the sole feedstock for ethanol biofuel production, the results of this investigation indicate that watermelon juice, either as whole juice fermented on-site or as a waste stream from neutraceutical production, could easily integrate with other more concentrated feedstocks where it could serve as diluent, supplemental feedstock, and nitrogen supplement.

Fish, Wayne W; Bruton, Benny D; Russo, Vincent M

2009-01-01

197

Engineering the push and pull of lipid biosynthesis in oleaginous yeast Yarrowia lipolytica for biofuel production.  

PubMed

Microbial oil production by heterotrophic organisms is a promising path for the cost-effective production of biofuels from renewable resources provided high conversion yields can be achieved. To this end, we have engineered the oleaginous yeast Yarrowia lipolytica. We first established an expression platform for high expression using an intron-containing translation elongation factor-1? (TEF) promoter and showed that this expression system is capable of increasing gene expression 17-fold over the intronless TEF promoter. We then used this platform for the overexpression of diacylglycerol acyltransferase (DGA1), the final step of the triglyceride (TAG) synthesis pathway, which yielded a 4-fold increase in lipid production over control, to a lipid content of 33.8% of dry cell weight (DCW). We also show that the overexpression of acetyl-CoA carboxylase (ACC1), the first committed step of fatty acid synthesis, increased lipid content 2-fold over control, or 17.9% lipid content. Next we combined the two genes in a tandem gene construct for the simultaneous coexpression of ACC1 and DGA1, which further increased lipid content to 41.4%, demonstrating synergistic effects of ACC1+DGA1 coexpression. The lipid production characteristics of the ACC1+DGA1 transformant were explored in a 2-L bioreactor fermentation, achieving 61.7% lipid content after 120h. The overall yield and productivity were 0.195g/g and 0.143g/L/h, respectively, while the maximum yield and productivity were 0.270g/g and 0.253g/L/h during the lipid accumulation phase of the fermentation. This work demonstrates the excellent capacity for lipid production by the oleaginous yeast Y. lipolytica and the effects of metabolic engineering of two important steps of the lipid synthesis pathway, which acts to divert flux towards the lipid synthesis and creates driving force for TAG synthesis. PMID:23026119

Tai, Mitchell; Stephanopoulos, Gregory

2013-01-01

198

Manipulation of the carbon storage regulator system for metabolite remodeling and biofuel production in Escherichia coli  

PubMed Central

Background Microbial engineering strategies that elicit global metabolic perturbations have the capacity to increase organism robustness for targeted metabolite production. In particular, perturbations to regulators of cellular systems that impact glycolysis and amino acid production while simultaneously decreasing fermentation by-products such as acetate and CO2 make ideal targets. Intriguingly, perturbation of the Carbon Storage Regulator (Csr) system has been previously implicated in large changes in central carbon metabolism in E. coli. Therefore, we hypothesized that perturbation of the Csr system through the CsrA-CsrB ribonucleoprotein complex might increase production of biofuels and their intermediates from heterologous pathways. Results We engaged the CsrA-CsrB ribonucleoprotein complex of E. coli via overexpression of CsrB. CsrB is a 350-nucleotide non-coding RNA that antagonizes CsrA, an RNA-binding protein that regulates translation of specific mRNA targets. By using shotgun proteomics and targeted metabolomics we established that elevation of CsrB levels leads to alterations in metabolite and protein levels in glycolysis, the TCA cycle and amino acid levels. Consequently, we show that such changes can be suitably applied to improve the production of desired compounds through the native fatty acid and heterologous n-butanol and isoprenoid pathways by up to two-fold. We also observed concomitant decreases in undesirable fermentation by-products such as acetate and CO2. Conclusions We have demonstrated that simple engineering of the RNA-based Csr global regulatory system constitutes a novel approach to obtaining pathway-independent improvements within engineered hosts. Additionally, since Csr is conserved across most prokaryotic species, this approach may also be amenable to a wide variety of production hosts.

2012-01-01

199

Closing the gap: global potential for increasing biofuel production through agricultural intensification  

NASA Astrophysics Data System (ADS)

Since the end of World War II, global agriculture has undergone a period of rapid intensification achieved through a combination of increased applications of chemical fertilizers, pesticides, and herbicides, the implementation of best management practice techniques, mechanization, irrigation, and more recently, through the use of optimized seed varieties and genetic engineering. However, not all crops and not all regions of the world have realized the same improvements in agricultural intensity. In this study we examine both the magnitude and spatial variation of new agricultural production potential from closing of 'yield gaps' for 20 ethanol and biodiesel feedstock crops. With biofuels coming under increasing pressure to slow or eliminate indirect land-use conversion, the use of targeted intensification via established agricultural practices might offer an alternative for continued growth. We find that by closing the 50th percentile production gap—essentially improving global yields to median levels—the 20 crops in this study could provide approximately 112.5 billion liters of new ethanol and 8.5 billion liters of new biodiesel production. This study is intended to be an important new resource for scientists and policymakers alike—helping to more accurately understand spatial variation of yield and agricultural intensification potential, as well as employing these data to better utilize existing infrastructure and optimize the distribution of development and aid capital.

Johnston, Matt; Licker, R.; Foley, J.; Holloway, T.; Mueller, N. D.; Barford, C.; Kucharik, C.

2011-07-01

200

State of the Art and Future Trends of Bioethanol Production  

Microsoft Academic Search

With efforts to reduce global reliance on fossil fuels and lower the greenhouse gas emission, an increasing search for renewably sourced materials, which can be used as feedstock for biofuel production, is ongoing in the past few decades. At the present, ethanol is the most common alternate fuel and is already produced on a fair scale, representing a sustainable substitute

Marcos A. das Neves; Toshinori Kimura; Naoto Shimizu; Mitsutoshi Nakajima

201

Oleaginous fungal lipid fermentation on combined acid- and alkali-pretreated corn stover hydrolysate for advanced biofuel production.  

PubMed

A combined hydrolysis process, which first mixed dilute acid- and alkali-pretreated corn stover at a 1:1 (w/w) ratio, directly followed by enzymatic saccharification without pH adjustment, has been developed in this study in order to minimize the need of neutralization, detoxification, and washing during the process of lignocellulosic biofuel production. The oleaginous fungus Mortierella isabellina was selected and applied to the combined hydrolysate as well as a synthetic medium to compare fungal lipid accumulation and biodiesel production in both shake flask and 7.5L fermentor. Fungal cultivation on combined hydrolysate exhibited comparable cell mass and lipid yield with those from synthetic medium, indicating that the integration of combined hydrolysis with oleaginous fungal lipid fermentation has great potential to improve performance of advanced lignocellulosic biofuel production. PMID:24768942

Ruan, Zhenhua; Zanotti, Michael; Archer, Steven; Liao, Wei; Liu, Yan

2014-07-01

202

Algal production in wastewater treatment high rate algal ponds for potential biofuel use.  

PubMed

Wastewater treatment High Rate Algal Ponds with CO2 addition could provide cost-effective and efficient tertiary-level wastewater treatment with the co-benefit of algal biomass production for biofuel use. Wastewater grown algal biomass can have a lipid content of 10-30% of dry weight, which could be used to make biodiesel. This research investigated algal biomass and total lipid production by two pilot-scale wastewater treatment HRAP(S) (4-day HRT) with and without CO2 addition under New Zealand mid summer (Nov-Jan) conditions. The influence of CO2 addition on wastewater treatment performance was also determined. CO2 was added to one of the HRAPs (the HRAP(E)) by maintaining the maximum pH of the pond below 8. Measurements of HRAP influent and effluent water qualities, total lipid content and algal biomass production were made twice a week over the experimental period. Both HRAP(S) achieved high levels of organic compound and nutrient removal, with >85% SBOD5, >92 NH4(+)-N and >70% DRP removal. Algal/bacterial biomass production in the HRAP(E) (15.2 g/m2/d) was improved by CO2 addition by approximately 30% compared with that of the control HRAP(W) (10.6 g/m2/d). Total lipid content of the biomass grown on both HRAP(S) was slightly reduced (from 25% to 20%) with CO2 addition and the maximum total lipid content of approximately 40% was observed in the HRAP(W) when low NH4(+)-N concentration (<0.5 mg/L) and high maximum pH (>10.0) occurred. Total lipid content of the biomass increased by approximately 15% under nitrogen limiting conditions, however, overall algal/bacterial biomass production was reduced by half during the period of nitrogen limitation. More research is required to maintain algal production under near nitrogen-limiting conditions. PMID:21977667

Park, J B K; Craggs, R J

2011-01-01

203

N2O release from agro-biofuel production negates global warming reduction by replacing fossil fuels  

NASA Astrophysics Data System (ADS)

The relationship, on a global basis, between the amount of N fixed by chemical, biological or atmospheric processes entering the terrestrial biosphere, and the total emission of nitrous oxide (N2O), has been re-examined, using known global atmospheric removal rates and concentration growth of N2O as a proxy for overall emissions. The relationship, in both the pre-industrial period and in recent times, after taking into account the large-scale changes in synthetic N fertiliser production and deforestation, is consistent, showing an overall conversion factor of 3-5%. This factor is covered only in part by the ~1% of "direct" emissions from agricultural crop lands estimated by IPCC (2006), or the "indirect" emissions cited therein. This means that the extra N2O entering the atmosphere as a result of using N to produce crops for biofuels will also be correspondingly greater than that estimated just on the basis of IPCC (2006). When the extra N2O emission from biofuel production is calculated in "CO2-equivalent" global warming terms, and compared with the quasi-cooling effect of "saving" emissions of fossil fuel derived CO2, the outcome is that the production of commonly used biofuels, such as biodiesel from rapeseed and bioethanol from corn (maize), can contribute as much or more to global warming by N2O emissions than cooling by fossil fuel savings. Crops with less N demand, such as grasses and woody coppice species have more favourable climate impacts. This analysis only considers the conversion of biomass to biofuel. It does not take into account the use of fossil fuel on the farms and for fertilizer and pesticide production, but it also neglects the production of useful co-products. Both factors partially compensate each other. This needs to be analyzed in a full life cycle assessment.

Crutzen, P. J.; Mosier, A. R.; Smith, K. A.; Winiwarter, W.

2007-08-01

204

Nanocrystalline cellulose extraction process and utilization of the byproduct for biofuels production.  

PubMed

Cellulose consists of amorphous and crystalline regions. It is the crystalline regions which may be exploited to produce nanocrystalline cellulose (NCC). In order to extract nanocrystalline cellulose from native cellulose, sulfuric acid hydrolysis is typically used. The amorphous regions of cellulose are hydrolyzed and degraded into soluble products while the crystalline regions remain intact. In an effort to make the NCC extraction process more feasible, a new process was developed to recover and utilize the hydrolyzed regions of cellulose as a byproduct. The acid hydrolyzed amorphous regions were separated and then recovered (regenerated) into solid particles. XRD data revealed that the recovered material is characteristic of cellulose II. Hydrolysis conditions were optimized to maximize the yield of the recovered material and at the same time produce NCC material. Preliminary experiments showed yield values of approximately 61% for the cellulose I crystalline portions and values of about 21.7% for the recovered material (cellulose II). Enzymatic hydrolysis experiments of the recovered material revealed high susceptibility to enzymatic hydrolysis which makes it a promising source for biofuels production. PMID:23465941

Pirani, Sanaa; Hashaikeh, Raed

2013-03-01

205

IPAD products and implications for the future  

NASA Technical Reports Server (NTRS)

The betterment of productivity through the improvement of product quality and the reduction of cost is addressed. Productivity improvement is sought through (1) reduction of required resources, (2) improved ask results through the management of such saved resources, (3) reduced downstream costs through manufacturing-oriented engineering, and (4) lowered risks in the making of product design decisions. The IPAD products are both hardware architecture and software distributed over a number of heterogeneous computers in this architecture. These IPAD products are described in terms of capability and engineering usefulness. The future implications of state-of-the-art IPAD hardware and software architectures are discussed in terms of their impact on the functions and on structures of organizations concerned with creating products.

Miller, R. E., Jr.

1980-01-01

206

Livestock production: recent trends, future prospects  

PubMed Central

The livestock sector globally is highly dynamic. In developing countries, it is evolving in response to rapidly increasing demand for livestock products. In developed countries, demand for livestock products is stagnating, while many production systems are increasing their efficiency and environmental sustainability. Historical changes in the demand for livestock products have been largely driven by human population growth, income growth and urbanization and the production response in different livestock systems has been associated with science and technology as well as increases in animal numbers. In the future, production will increasingly be affected by competition for natural resources, particularly land and water, competition between food and feed and by the need to operate in a carbon-constrained economy. Developments in breeding, nutrition and animal health will continue to contribute to increasing potential production and further efficiency and genetic gains. Livestock production is likely to be increasingly affected by carbon constraints and environmental and animal welfare legislation. Demand for livestock products in the future could be heavily moderated by socio-economic factors such as human health concerns and changing socio-cultural values. There is considerable uncertainty as to how these factors will play out in different regions of the world in the coming decades.

Thornton, Philip K.

2010-01-01

207

Fuel for the Future: Development of New Fuels, e.g. Biofuels  

NASA Astrophysics Data System (ADS)

Whether we like it or not, climate change is to some extent affiliated with the emission of green house gasses, and specifically CO2 emissions, which are rising due to the global increased use of fossil fuels. As a result, political enthusiasm is high when it comes to implementing new initiatives aimed at better protection of the global environment. However, environmental concerns are just one aspect of the issues associated with the use of fossil fuels, since fossil fuels are a natural reserve and, therefore, a limited resource. Prognoses vary, but within the next decades the fossil fuel reserves will be exhausted leading to reduced oil production, rising oil prices, and the risk of international bellicose conflicts caused by adverse national interests. Additionally, fossil fuel as a natural reserve is unevenly distributed, meaning that a few countries possess the main energy reserve of the entire world. The incorporation of alternatives to fossil fuel into the existing fuel infrastructure is currently under intense development in the Western world, both to cut the oil dependency and to counter the depletion of oil reserves. This political enthusiasm to decrease the use of fossil fuel is emphasised by the fact that according to the International Energy Agency (IEA) more than 80% of the global primary energy consumption in 2007 accounts from fossil fuels and half of this is oil. More than 60% of the oil is used in the transport sector.

Sørensen, Gitte; Sørensen, Ketil Bernt; Hansen, Hans Ove; Nygaard, Sune D.

208

Neochloris oleabundans UTEX #1185: a suitable renewable lipid source for biofuel production.  

PubMed

Energy crises, global warming, and climatic changes call for technological and commercial advances in manufacturing high-quality transportation fuels from unconventional feedstocks. Microalgae is one of the most promising sources of biofuels due to the high yields attained per unit area and because it does not displace food crops. Neochloris oleabundans (Neo) microalga is an important promising microbial source of single-cell oil (SCO). Different experimental growth and lipid production conditions were evaluated and compared by using optical density (540 nm), dry-weight determination, and flow cytometry (FC). Best Neo average biomass productivity was obtained at 30 degrees C under conditions of nitrogen-sufficiency and CO(2) supplementation (N+/30 degrees C/CO(2)), with an average doubling time of 1.4 days. The second and third highest productivities occurred with N-sufficient cultures without CO(2) supplementation at 26 degrees C (N+/26 degrees C) and at 30 degrees C (N+/30 degrees C), with doubling times of 1.7 and 2.2 days, respectively. Microbial lipid production was monitored by flow cytometry using Nile red (NR), a lipophilic fluorochrome that possesses several advantageous characteristics for in situ screening near real time (at line). Results showed maximum lipid content (56%) after 6 days of nitrogen depletion under nitrogen starvation without CO(2) supplementation (N-/30 degrees C), followed by N-/30 degrees C/CO(2) and N-/26 degrees C conditions with 52% lipid content, after 5 and 6 days of N starvation, respectively. The adequate fatty acid profile and iodine value of Neo lipids reinforced this microalga as a good source of SCO, in particular for use as biodiesel. PMID:19377896

Gouveia, Luísa; Marques, Ana Evangelista; da Silva, Teresa Lopes; Reis, Alberto

2009-06-01

209

Metabolic Engineering of Clostridium thermocellum for Biofuel Production (2013 DOE JGI Genomics of Energy and Environment 8th Annual User Meeting)  

SciTech Connect

Adam Guss of Oak Ridge National Lab on "Metabolic engineering of Clostridium thermocellum for biofuel production" at the 8th Annual Genomics of Energy & Environment Meeting on March 28, 2013 in Walnut Creek, Calif.

Guess, Adam [ORNL

2013-03-01

210

Ecopolis: Biofuels  

NSDL National Science Digital Library

This 3-minute video explains how algae, a biofuel, is being developed as an energy source. It also discusses disadvantages of current biofuels and how algae will overcome these disadvantages. The site also provides links to videos about related topics.

Channel, Science

211

Effect of catalyst additives on the production of biofuels from palm oil cracking in a transport riser reactor  

Microsoft Academic Search

Catalytic cracking of crude palm oil (CPO) and used palm oil (UPO) were studied in a transport riser reactor for the production of biofuels at a reaction temperature of 450°C, with residence time of 20s and catalyst-to-oil ratio (CTO) of 5gg?1. The effect of HZSM-5 (differrent Si\\/Al ratios), beta zeolite, SBA-15 and AlSBA-15 were studied as physically mixed additives with

Thiam Leng Chew; Subhash Bhatia

2009-01-01

212

Production of biofuel from waste cooking palm oil using nanocrystalline zeolite as catalyst: process optimization studies.  

PubMed

The catalytic cracking of waste cooking palm oil to biofuel was studied over different types of nano-crystalline zeolite catalysts in a fixed bed reactor. The effect of reaction temperature (400-500 °C), catalyst-to-oil ratio (6-14) and catalyst pore size of different nanocrystalline zeolites (0.54-0.80 nm) were studied over the conversion of waste cooking palm oil, yields of Organic Liquid Product (OLP) and gasoline fraction in the OLP following central composite design (CCD). The response surface methodology was used to determine the optimum value of the operating variables for maximum conversion as well as maximum yield of OLP and gasoline fraction, respectively. The optimum reaction temperature of 458 °C with oil/catalyst ratio=6 over the nanocrystalline zeolite Y with pore size of 0.67 nm gave 86.4 wt% oil conversion, 46.5 wt% OLP yield and 33.5 wt% gasoline fraction yield, respectively. The experimental results were in agreement with the simulated values within an experimental error of less than 5%. PMID:21924606

Taufiqurrahmi, Niken; Mohamed, Abdul Rahman; Bhatia, Subhash

2011-11-01

213

Algae harvesting for biofuel production: Influences of UV irradiation and polyethylenimine (PEI) coating on bacterial biocoagulation.  

PubMed

There is a pressing need to develop efficient and sustainable separation technologies to harvest algae for biofuel production. In this work, two bacterial species (Escherichia coli and Rhodococus sp.) were used as biocoagulants to harvest Chlorella zofingiensis and Scenedesmus dimorphus. The influences of UV irradiation and polyethylenimine (PEI)-coating on the algal harvesting efficiency were investigated. Results showed that the UV irradiation could slightly enhance bacteria-algae biocoagulation and algal harvesting efficiency. In contrast, the PEI-coated E. coli cells noticeably increased the harvesting efficiencies from 23% to 83% for S. dimorphus when compared to uncoated E. coli cells. Based on the soft-particle Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, an energy barrier existed between uncoated E. coli cells and algal cells, whereas the PEI coating on E. coli cells eliminated the energy barrier, thereby the biocoagulation was significantly improved. Overall, this work presented groundwork toward the potential use of bacterial biomass for algal harvesting from water. PMID:24926598

Agbakpe, Michael; Ge, Shijian; Zhang, Wen; Zhang, Xuezhi; Kobylarz, Patricia

2014-08-01

214

Toward systems metabolic engineering of Aspergillus and Pichia species for the production of chemicals and biofuels.  

PubMed

Recently genome sequence data have become available for Aspergillus and Pichia species of industrial interest. This has stimulated the use of systems biology approaches for large-scale analysis of the molecular and metabolic responses of Aspergillus and Pichia under defined conditions, which has resulted in much new biological information. Case-specific contextualization of this information has been performed using comparative and functional genomic tools. Genomics data are also the basis for constructing genome-scale metabolic models, and these models have helped in the contextualization of knowledge on the fundamental biology of Aspergillus and Pichia species. Furthermore, with the availability of these models, the engineering of Aspergillus and Pichia is moving from traditional approaches, such as random mutagenesis, to a systems metabolic engineering approach. Here we review the recent trends in systems biology of Aspergillus and Pichia species, highlighting the relevance of these developments for systems metabolic engineering of these organisms for the production of hydrolytic enzymes, biofuels and chemicals from biomass. PMID:23576362

Caspeta, Luis; Nielsen, Jens

2013-05-01

215

Directed evolution of a cellodextrin transporter for improved biofuel production under anaerobic conditions in Saccharomyces cerevisiae.  

PubMed

Introduction of a cellobiose utilization pathway consisting of a cellodextrin transporter and a ?-glucosidase into Saccharomyces cerevisiae enables co-fermentation of cellobiose and xylose. Cellodextrin transporter 1 (CDT1) from Neurospora crassa has been established as an effective transporter for the engineered cellobiose utilization pathways. However, cellodextrin transporter 2 (CDT2) from the same species is a facilitator and has the potential to be more efficient than CDT1 under anaerobic conditions due to its energetic benefits. Currently, CDT2 has a very low activity and is considered rate-limiting in cellobiose fermentation. Here, we report the directed evolution of CDT2 with an increased cellobiose uptake activity, which results in improved cellobiose fermentation under anaerobic conditions. After three rounds of directed evolution, the cellobiose uptake activity of CDT2 was increased by 2.2-fold, which resulted from both increased specific activity and transporter expression level. Using high cell density fermentation under anaerobic conditions, the evolved mutant conferred 4.0- and 4.4-fold increase in the cellobiose consumption rate and ethanol productivity, respectively. In addition, although the cellobiose uptake activity was still lower than that of CDT1, the engineered CDT2 showed significantly improved cellobiose consumption and ethanol production under anaerobic conditions, representing the energetic benefits of a sugar facilitator for anaerobic cellobiose fermentation. This study demonstrated that anaerobic biofuel production could be significantly improved via directed evolution of a sugar transporter protein in yeast. Biotechnol. Bioeng. 2014;111: 1521-1531. © 2014 Wiley Periodicals, Inc. PMID:24519319

Lian, Jiazhang; Li, Yanglin; HamediRad, Mohammad; Zhao, Huimin

2014-08-01

216

Liquid biofuels - can they meet our expectations?  

NASA Astrophysics Data System (ADS)

Liquid biofuels are one of the options for reducing the emission of greenhouse gases and the dependence on fossil fuels. This is reflected in the DIRECTIVE 2003/30/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL on the promotion of the use of biofuels or other renewable fuels for transport. The promotion of E10, an automotive fuel containing 10 percent bioethanol, is based on this directive. At present almost all bioethanol is produced from agricultural crops such as maize, corn or sugar beet and sugar cane in suitable climates. In view of shortages and rising prices of food, in particular in developing countries, the use of food and feed crops for biofuel production is increasingly criticized. Alternative sources of biomass are perennial grasses and wood, whose cellulose fraction can be converted to alcohol by the so called "second generation" processes, which seem to be close to commercial deployment. The use of the total plant biomass increases the biofuel yield per hectare as compared to conventional crops. Of special interest for biofuel production is woody biomass from forests as this avoids competition with food production on arable land. Historically woody biomass was for millennia the predominant source of thermal energy. Before fossil fuels came into use, up to 80 percent of a forest was used for fuel wood, charcoal and raw materials such as potash for trade and industry. Now forests are managed to yield up to 80 percent of high grade timber for the wood industry. Replacing sophisticatedly managed forests by fast growing biofuel plantations could make economic sense for land owners when a protected market is guaranteed by politics, because biofuel plantations would be highly mechanized and cheap to operate, even if costs for certified planting material and fertilizer are added. For forest owners the decision to clear existing long rotation forests for biofuel plantations would still be weighty because of the extended time of decades required to rebuild a timber forest if alternative fuel sources would outcompete biofuels in the future. Because second generation bioethanol plants are technically complex and will require substantial amounts of biomass - at least at current perception - the impact of large scale conversion of arable and forests to biofuel plantations on biodiversity, ground water, rural communities, tourism as well as traffic and transport, just to mention a few, must be considered. Another factor is storability of biomass. Whole plant and woody biomass is much more difficult to store than grains and a steady flux from the plantation to the mill might be difficult to sustain under adverse weather conditions.

Glatzel, G.

2012-04-01

217

Factors Driving Biofuel Crops' Influence on Climate  

NASA Astrophysics Data System (ADS)

Large scale deployment of new biofuel crops has the potential to influence climate through biogeophysical and biogeochemical mechanisms operating at the land surface. In turn, climatic variability influences the productivity of biofuel crops and thus their potential contribution as a source of energy. In order to characterize this two-way interaction between biofuels and climate, we are conducting a series of modeling experiments within the National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM). Key questions that this study attempts to address include 1) In what ways (e.g. at what spatial and temporal scales, under what land cover and management scenarios) does a transition to biofuel crops represent a climate stabilizing versus a climate destabilizing endeavor? 2) Which vegetation properties and management choices are most influential in determining key climatic outcomes associated with biofuels? 3) Are biofuel crop yields robust to changing climatic conditions? Our approach is to develop new biofuel plant functional types (PFTs) for the land surface component of CESM - the Community Land Model (CLM) - and to examine climatic implications of future biofuel deployment scenarios within the coupled land-atmosphere framework of CESM. We are focusing initially on c4 grass crops - i.e. switchgrass, miscnathus, sugarcane, and maize. CLM represents plant functional types with more than 50 parameters that describe aerodynamic, physiological, optical, and biogeochemical properties etc. We are also making structural modification to the model in order to represent unique features of biofuel crops and their management, such as changes to the phenology and carbon allocation schema for c4 grasses. Detailed observational data from new biofuel crops such as switchgrass and miscanthus is limited and offers a weak constraint on the full set of PFT parameters. To address this problem, we are conducting systematic sensitivity analysis on the default c4 grass parameters in CLM in order to identify a smaller set of parameters that exerts the most control on climatically relevant terms such as energy and carbon fluxes. By revealing those parameters that are most and least influential in terms of climate forcing, systematic sensitivity analysis helps to prioritize the search for observational data, constrains the process of tuning parameters to limited data, and leads the way to characterizing the uncertainty in biofuel crops’ influence on climate. Furthermore, due to similarities across managed ecosystems, these results offer general insight into those plant physiological properties and management factors that must be well-characterized in order to model changes in energy and carbon fluxes resulting from human land use.

Jones, A.; Torn, M. S.; Riley, W. J.; Collins, W.

2010-12-01

218

Biofuels: balancing risks and rewards.  

PubMed

This paper describes a framework that can be used to evaluate the environmental risks and benefits associated with biofuel production. It uses the example of biodiesel produced from Argentinean soy to show how such a framework can be used to conceptualize trade-offs between different environmental, social and economic impacts of biofuel production. Results showing the greenhouse-gas savings and overall life-cycle impact of different 'soy-biodiesel' production methods are presented. These impacts and the significance of uncertainty in overall assessments of key parameters, such as greenhouse-gas savings, are discussed. It is shown that, even where sufficient knowledge exists to be able to quantify these impacts, the sustainability of supply of a particular biofuel is inextricably linked to values and ethical judgements. However, tailoring certification efforts to the issues that are most likely to make a significant difference to the overall sustainability could improve the effectiveness of certification efforts. The potential for a framework to guide and focus certification efforts is discussed and future research and policy priorities suggested. PMID:24427513

Thornley, Patricia; Gilbert, Paul

2013-02-01

219

Spatial Optimization of Cropping Pattern in an Agricultural Watershed for Food and Biofuel Production with Minimum Downstream Pollution  

NASA Astrophysics Data System (ADS)

Biofuel is considered to be a viable alternative to meet the increasing fuel demand, and therefore many countries are promoting agricultural activities that help increase production of raw material for biofuel production. Mostly, the biofuel is produced from grain based crops such as Corn, and it apparently create a shortage in food grains. Consequently, there have been regulations to limit the ethanol production from grains, and to use cellulosic crops as raw material for biofuel production. However, cultivation of such cellulosic crops may have different effects on water quality in the watershed. Corn stover, one of the potential cellulosic materials, when removed from the agricultural field for biofuel production, causes a decrease in the organic nutrients in the field. This results in increased use of pesticides and fertilizers which in turn affect the downstream water quality due to leaching of the chemicals. On the contrary, planting less fertilizer-intensive cellulosic crops, like Switch Grass and Miscanthus, is expected to reduce the pollutant loadings from the watershed. Therefore, an ecologically viable land use scenario would be a mixed cropping of grain crops and cellulosic crops, that meet the demand for food and biofuel without compromising on the downstream water quality. Such cropping pattern can be arrived through a simulation-optimization framework. Mathematical models can be employed to evaluate various management scenarios related to crop production and to assess its impact on water quality. Soil and Water Assessment Tool (SWAT) model is one of the most widely used models in this context. SWAT can simulate the water and nutrient cycles, and also quantify the long-term impacts of land management practices, in a watershed. This model can therefore help take decisions regarding the type of cropping and management practices to be adopted in the watershed such that the water quality in the rivers is maintained at acceptable level. In this study, it is proposed to link SWAT model with an optimization algorithm, whose objective is to identify the optimal cropping pattern that results in maximum biomass production for biofuel generation as well as a minimum guaranteed amount of grain production. The optimal allocation ensures that the downstream water quality in the river is within a desirable limit. The study employed probabilistic information in order to address the uncertainty in model simulations. The residual variance of the model is used to transform the deterministic simulations in to probabilistic information. The proposed framework is illustrated using data pertaining to an agricultural watershed in the USA. The preliminary results of the study are encouraging and suggest that an appropriate combination of Corn, Soyabean, Miscanthus, Switch Grass and Pasture land can be arrived at through the developed framework. The placement of Miscanthus and Switch Grass in the watershed help improve the downstream water quality, while Corn and Soyabean makes it deteriorated. The spatial allocation of these crops therefore certainly plays a major role in the downstream water quality.

Pv, F.; Sudheer, K.; Chaubey, I.; RAJ, C.; Her, Y.

2013-05-01

220

Biofuels combustion.  

PubMed

This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acids and used primarily to replace or supplement conventional diesel fuels. Research efforts on so-called second- and third-generation biofuels are discussed briefly. PMID:23298249

Westbrook, Charles K

2013-01-01

221

Large-scale production of diesel-like biofuels - process design as an inherent part of microorganism development.  

PubMed

Industrial biotechnology is playing an important role in the transition to a bio-based economy. Currently, however, industrial implementation is still modest, despite the advances made in microorganism development. Given that the fuels and commodity chemicals sectors are characterized by tight economic margins, we propose to address overall process design and efficiency at the start of bioprocess development. While current microorganism development is targeted at product formation and product yield, addressing process design at the start of bioprocess development means that microorganism selection can also be extended to other critical targets for process technology and process scale implementation, such as enhancing cell separation or increasing cell robustness at operating conditions that favor the overall process. In this paper we follow this approach for the microbial production of diesel-like biofuels. We review current microbial routes with both oleaginous and engineered microorganisms. For the routes leading to extracellular production, we identify the process conditions for large scale operation. The process conditions identified are finally translated to microorganism development targets. We show that microorganism development should be directed at anaerobic production, increasing robustness at extreme process conditions and tailoring cell surface properties. All the same time, novel process configurations integrating fermentation and product recovery, cell reuse and low-cost technologies for product separation are mandatory. This review provides a state-of-the-art summary of the latest challenges in large-scale production of diesel-like biofuels. PMID:23650260

Cuellar, Maria C; Heijnen, Joseph J; van der Wielen, Luuk A M

2013-06-01

222

Energy crops for biofuel feedstocks: facts and recent patents on genetic manipulation to improve biofuel crops.  

PubMed

Burning fossil-fuels to meet the global energy requirements by human being has intensified the concerns of increasing concentrations of greenhouse gases. Therefore, serious efforts are required to develop nonfossil-based renewable energy sources. Plants are more efficient in utilizing solar energy to convert it into biomass which can be used as feedstocks for biofuel production. Hence with the increasing demands of energy and the needs of cost-effective, sustainable production of fuels, it has become necessary to switch over to plant biomass as a renewable source of energy. Biofuels derived from more sustainable biological materials such as lignocellulosic plant residues, considered as second generation biofuels, are more dependable. However, there are technical challenges such as pretreatment and hydrolysis of lignocellulosic biomass to convert it into fermentable sugars. Plant genetic engineering has already proven its potential in modifying cell wall composition of plants for enhancing the efficiency of biofuel production. Interest and potential in the area are very much evident from the growing number of patents in the recent years on the subject. In this review, recent trends in genetic engineering of energy crops for biofuel production have been introduced, and strategies for the future developments have been discussed. PMID:24456235

Kumar, Suresh

2013-12-01

223

Present and Future IGS Ionospheric Products  

NASA Astrophysics Data System (ADS)

The purpose of this paper is, on one hand, to show the present performance of the combined final and rapid IGS global ionosphere maps (GIMs), and on the other hand to inform the geodetic community on new product - predicted IGS GIMs. In addition, information on future development of IGS ionospheric products will be also presented. Nowadays, the Ionosphere Working Group of IGS generates three types of ionospheric products: final, rapid and predicted, respectively. There are currently four IGS Associate Analysis Centres (IAACs) for the ionospheric products: CODE (Center for Orbit Determination in Europe, University of Berne, Switzerland), ESA/ESOC (European Space Operations Center of ESA, Darmstadt, Germany), JPL (Jet Propulsion Laboratory, Pasadena, U.S.A) and gAGE/UPC (Technical University of Catalonia, Barcelona, Spain). These centres provide ionosphere maps computed with different approaches. Their maps are uploaded to IGS Ionosphere Product Coordinator, who computes official IGS combined products. Since January 2008, this coordination is carried out by the GRL/UWM (Geodynamics Research Laboratory of the University of Warmia and Mazury in Olsztyn, Poland). The IGS GIMs are provided in Ionosphere Exchange (IONEX) format with spatial resolution of 5.0 degrees in longitude and 2.5 degrees in latitude, and temporal resolution of 2 hours. Latency of the final and rapid GIMs is 10 days and 1 day, respectively. In November 2009, the IGS Iono WG started to generate predicted ionospheric products 1 and 2 days in advance (requested for ESA's SMOS mission). These new IGS products are currently based on predicted ionosphere maps prepared by UPC and ESA. During period of more than 10 years of continuous IGS ionosphere operation, the techniques used by the IAACs and the strategies of combination have improved in such a way that the combined IGS GIMs are now significantly more accurate and robust. Future plans include, among others, increasing temporal resolution to 1 hour and studies on taking advantage of COSMIC occultation data.

Krankowski, Andrzej; Wielgosz, Pawel; Hernández-Pajares, Manuel; García-Rigo, Alberto

2010-05-01

224

Satellite-based assessment of water requirement for biofuel feedstock production in Maui, Hawaii  

NASA Astrophysics Data System (ADS)

Water availability is one of the limiting factors for sustainable production of biofuel crops. A common method for determining crop water requirement is to multiply daily potential evapotranspiration (ETo) calculated from meteorological parameters by a crop coefficient (Kc) to obtain actual crop evapotranspiration (ETc). Remote sensing data can provide dynamic Kc values that better reflect plant water use. In this study, an algorithm is being developed to estimate sugarcane Kc using normalized difference vegetation index (NDVI) obtained from Landsat 7 satellite images. Crop canopy cover was measured with a handheld multispectral camera from two sugarcane fields at the Hawaiian Commercial & Sugar Company (HC&S) plantation during the Landsat 7 satellite overpass days. An Eddy Covariance (EC) tower system was set up within each of these two fields and gathered EC flux at a 30-minute interval. Reference evapotranspiration was calculated from the network of automated weather stations at HC&S plantation using a modified Penman equation. Crop canopy cover was highly correlated with satellite NDVI values. A linear relationship between NDVI and measured Kc was obtained. Satellite -based ETc maps of HC&S plantation were developed using the NDVI-based Kc values and reference ET from HC&S weather station network. The satellite-based ETc was compared and validated with field measurements of ET using Eddy Covariance tower. A series of satellite-based ETc maps were developed to indicate the water demand of sugarcane plants at HC&S plantation. These results validate the use of satellite imagery as a tool for estimation of ET of sugarcane plants in Maui, Hawaii.

Zhang, H.; Anderson, R. G.; Wang, D.

2012-12-01

225

N2O release from agro-biofuel production negates global warming reduction by replacing fossil fuels  

NASA Astrophysics Data System (ADS)

The relationship, on a global basis, between the amount of N fixed by chemical, biological or atmospheric processes entering the terrestrial biosphere, and the total emission of nitrous oxide (N2O), has been re-examined, using known global atmospheric removal rates and concentration growth of N2O as a proxy for overall emissions. For both the pre-industrial period and in recent times, after taking into account the large-scale changes in synthetic N fertiliser production, we find an overall conversion factor of 3-5% from newly fixed N to N2O-N. We assume the same factor to be valid for biofuel production systems. It is covered only in part by the default conversion factor for "direct" emissions from agricultural crop lands (1%) estimated by IPCC (2006), and the default factors for the "indirect" emissions (following volatilization/deposition and leaching/runoff of N: 0.35-0.45%) cited therein. However, as we show in the paper, when additional emissions included in the IPCC methodology, e.g. those from livestock production, are included, the total may not be inconsistent with that given by our "top-down" method. When the extra N2O emission from biofuel production is calculated in "CO2-equivalent" global warming terms, and compared with the quasi-cooling effect of "saving" emissions of fossil fuel derived CO2, the outcome is that the production of commonly used biofuels, such as biodiesel from rapeseed and bioethanol from corn (maize), depending on N fertilizer uptake efficiency by the plants, can contribute as much or more to global warming by N2O emissions than cooling by fossil fuel savings. Crops with less N demand, such as grasses and woody coppice species, have more favourable climate impacts. This analysis only considers the conversion of biomass to biofuel. It does not take into account the use of fossil fuel on the farms and for fertilizer and pesticide production, but it also neglects the production of useful co-products. Both factors partially compensate each other. This needs to be analyzed in a full life cycle assessment.

Crutzen, P. J.; Mosier, A. R.; Smith, K. A.; Winiwarter, W.

2008-01-01

226

Sustainable biofuels from algae  

Microsoft Academic Search

There is currently great interest in microalgae as sources of renewable energy and biofuels. Many algae species have a high\\u000a lipid content and can be grown on non-arable land using alternate water sources such as seawater. This paper discusses in\\u000a detail the issue of sustainability of commercial-scale microalgae production of biofuels with particular focus on land, water,\\u000a nutrients (N and

Michael Armin Borowitzka; Navid Reza Moheimani

227

Catalytic cracking of palm oil for the production of biofuels: Optimization studies  

Microsoft Academic Search

Oil palm is widely grown in Malaysia. Palm oil has attracted the attention of researchers to develop an ‘environmentally friendly’ and high quality fuel, free of nitrogen and sulfur. In the present study, the catalytic cracking of palm oil to biofuel was studied over REY catalyst in a transport riser reactor at atmospheric pressure. The effect of reaction temperature (400–500°C),

Pramila Tamunaidu; Subhash Bhatia

2007-01-01

228

Enzymatic activity and microbial biomass in soil amended with biofuel production byproducts  

Microsoft Academic Search

This study examined the effect of addition of byproducts generated from the biofuel industry on soil quality as measured by response of soil enzyme activity, microbial biomass C (MBC) and N (MBN) content and microbial quotient (MQ) to the addition of these materials over a short period of incubation. Byproducts of ethanol manufacture utilized included: wet distillers grain (WDG) and

Khaled D. Alotaibi; Jeff J. Schoenau

2011-01-01

229

Sustainability of algal biofuel production using integrated renewable energy park (IREP) and algal biorefinery approach  

Microsoft Academic Search

Algal biomass can provide viable third generation feedstock for liquid transportation fuel. However, for a mature commercial industry to develop, sustainability as well as technological and economic issues pertinent to algal biofuel sector must be addressed first. This viewpoint focuses on three integrated approaches laid out to meet these challenges. Firstly, an integrated algal biorefinery for sequential biomass processing for

Bobban G. Subhadra

2010-01-01

230

Optimization of Biofuel and Biochar Production from the Slow Pyrolysis of Biomass  

Microsoft Academic Search

Slow pyrolysis was performed on biomass samples (i.e., energy cane and air potato) to determine the most energy efficient conditions for producing biofuel and biochar. The potential of air potato as a source of fuel and char was also investigated. Dry biomass samples of 10, 15 and 20 g were heated in a reactor at a final temperatures of 300,

J. Fang; B. Gao

2010-01-01

231

Bioprospecting for hyper-lipid producing microalgal strains for sustainable biofuel production  

Microsoft Academic Search

Global petroleum reserves are shrinking at a fast pace, increasing the demand for alternate fuels. Microalgae have the ability to grow rapidly, and synthesize and accumulate large amounts (approximately 20–50% of dry weight) of neutral lipid stored in cytosolic lipid bodies. A successful and economically viable algae based biofuel industry mainly depends on the selection of appropriate algal strains. The

T. Mutanda; D. Ramesh; S. Karthikeyan; S. Kumari; A. Anandraj; F. Bux

2011-01-01

232

Improving the environmental performance of biofuels with industrial symbiosis  

Microsoft Academic Search

In the production of biofuels for transport many critics have argued about the poor energy efficiency and environmental performance of the production industries. Optimism is thus set on the production of second generation biofuels, while first generation biofuels continue to dominate worldwide. Therefore it is interesting to consider how the environmental performance of first generation biofuel industries can be improved.

Michael Martin; Mats Eklund

2011-01-01

233

The legitimacy of biofuel certification  

Microsoft Academic Search

The biofuel boom is placing enormous demands on existing cropping systems, with the most crucial consequences in the agri-food\\u000a sector. The biofuel industry is responding by initiating private governance and certification. The Roundtable on Sustainable\\u000a Palm Oil (RSPO) and the Cramer Commission, among others, have formulated criteria on “sustainable” biofuel production and\\u000a processing. This article explores the legitimacy of private

Lena Partzsch

2011-01-01

234

Effect of catalyst additives on the production of biofuels from palm oil cracking in a transport riser reactor.  

PubMed

Catalytic cracking of crude palm oil (CPO) and used palm oil (UPO) were studied in a transport riser reactor for the production of biofuels at a reaction temperature of 450 degrees C, with residence time of 20s and catalyst-to-oil ratio (CTO) of 5 gg(-1). The effect of HZSM-5 (different Si/Al ratios), beta zeolite, SBA-15 and AlSBA-15 were studied as physically mixed additives with cracking catalyst Rare earth-Y (REY). REY catalyst alone gave 75.8 wt% conversion with 34.5 wt% of gasoline fraction yield using CPO, whereas with UPO, the conversion was 70.9 wt% with gasoline fraction yield of 33.0 wt%. HZSM-5, beta zeolite, SBA-15 and AlSBA-15 as additives with REY increased the conversion and the yield of organic liquid product. The transport riser reactor can be used for the continuous production of biofuels from cracking of CPO and UPO over REY catalyst. PMID:19138514

Chew, Thiam Leng; Bhatia, Subhash

2009-05-01

235

Turning Bacteria into Fuel: Cyanobacteria Designed for Solar-Powered Highly Efficient Production of Biofuels  

SciTech Connect

Broad Funding Opportunity Announcement Project: ASU is engineering a type of photosynthetic bacteria that efficiently produce fatty acids—a fuel precursor for biofuels. This type of bacteria, called Synechocystis, is already good at converting solar energy and carbon dioxide (CO2) into a type of fatty acid called lauric acid. ASU has modified the organism so it continuously converts sunlight and CO2 into fatty acids—overriding its natural tendency to use solar energy solely for cell growth and maximizing the solar-to-fuel conversion process. ASU’s approach is different because most biofuels research focuses on increasing cellular biomass and not on excreting fatty acids. The project has also identified a unique way to convert the harvested lauric acid into a fuel that can be easily blended with existing transportation fuels.

None

2010-01-01

236

Biofuel production with CCS as a strategy for creating a CO 2 -neutral road transport sector  

Microsoft Academic Search

In this paper, three biofuel-producing processes with carbon dioxide capture and storage (CCS) are studied: two (fermentation) ethanol processes and one process producing methanol (via gasification). In these processes CO2 is captured from streams which are relatively pure, i.e. the main impurity is water vapour which may be easily removed. Owing to this, the costs for CO2 capture, both in

Erik G. Lindfeldt; Mats O. Westermark

2009-01-01

237

Viscous effects in the acoustic manipulation of algae for biofuel production  

Microsoft Academic Search

Microalgae are emerging as a promising source for environmentally friendly biofuels. Acoustic manipulation of algal cells\\u000a using standing waves is a relatively new method for dewatering and\\/or sorting algae harvests. Recent work in the field has\\u000a shown that acoustic dewatering methods may be more efficient and economical than traditional methods. Optimization of acoustic\\u000a algal cell manipulation requires a knowledge of

Cara A. C. Leckey; Mark K. Hinders

238

Unintended Consequences of Biofuels Production: The Effects of Large-Scale Crop Conversion on Water Quality and Quantity.  

National Technical Information Service (NTIS)

In the search for renewable fuel alternatives, biofuels have gained strong political momentum. In the last decade, extensive mandates, policies, and subsidies have been adopted to foster the development of a biofuels industry in the United States. The Bio...

C. T. Green H. L. Welch J. R. B. Barlow M. B. Hicks R. A. Rebich

2010-01-01

239

An Assessment of Land Availability and Price in the Coterminous United States for Conversion to Algal Biofuel Production  

SciTech Connect

Realistic economic assessment of land-intensive alternative energy sources (e.g., solar, wind, and biofuels) requires information on land availability and price. Accordingly, we created a comprehensive, national-scale model of these parameters for the United States. For algae-based biofuel, a minimum of 1.04E+05 km2 of land is needed to meet the 2022 EISA target of 2.1E+10 gallons year-1. We locate and quantify land types best converted. A data-driven model calculates the incentive to sell and a fair compensation value (real estate and lost future income). 1.02E+6 km2 of low slope, non-protected land is relatively available including croplands, pasture/ grazing, and forests. Within this total there is 2.64E+5 km2 of shrub and barren land available. The Federal government has 7.68E+4 km2 available for lease. Targeting unproductive lands minimizes land costs and impacts to existing industries. However, shrub and barren lands are limited by resources (water) and logistics, so land conversion requires careful consideration.

Venteris, Erik R.; Skaggs, Richard; Coleman, Andre M.; Wigmosta, Mark S.

2012-12-01

240

Biofuels and Biotechnology  

SciTech Connect

The world obtains 86% of its energy from fossil fuels, 40% from petroleum, a majority of which goes to the transportation sector (www.IEA.gov). Well-recognized alternatives are fuels derived from renewable sources known as biofuels. There are a number of biofuels useful for transportation fuels, which include ethanol, biobutanol, mixed alcohols, biodiesel, and hydrogen. These biofuels are produced from biologically derived feedstock, almost exclusively being plant materials, either food or feed sources or inedible plant material called biomass. This chapter will discuss technologies for production of liquid transportation biofuels from renewable feedstocks, but hydrogen will not be included, as the production technology and infrastructure are not near term. In addition, a specific emphasis will be placed upon the research opportunities and potential for application of system biology tools to dissect and understand the biological processes central to production of these biofuels from biomass and biological materials. There are a number of technologies for production of each of these biofuels that range from fully mature processes such as grain-derived ethanol, emerging technology of ethanol form cellulose derived ethanol and immature processes such thermochemical conversion technologies and production of hydrogen all produced from renewable biological feedstocks. Conversion of biomass by various thermochemical and combustion technologies to produce thermochemical biodiesel or steam and electricity provide growing sources of bioenergy. However, these technologies are outside of the scope of this chapter, as is the use of biological processing for upgrading and conversion of fossil fuels. Therefore, this chapter will focus on the current status of production of biofuels produced from biological-derived feedstocks using biological processes. Regardless of the status of development of the biological process for production of the biofuels, each process can benefit from research and resulting development activities using the latest biological research tools and techniques. Among the most recently evolving research tools is what is collectively known as "omics" techniques such as genomics, transcriptomics, proteomics, metabolomics, and fluxomics, plus an ever growing omics word generation . These and other similar methodologies are central to understanding the interactive functioning of gene expression, resulting protein/enzyme production, which impacts the cellular metabolism, and carbon and metabolite flow. These system biology "omics" tools are beginning to be applied to understand and improve the biological processes involved in conversion of renewable plant and animal material to biofuels which will be discussed in this chapter.

Mielenz, Jonathan R [ORNL

2009-01-01

241

A New Biofuels Technology Blooms in Iowa  

ScienceCinema

Cellulosic biofuels made from agricultural waste have caught the attention of many farmers and could be the next revolution in renewable biofuels production. This video shows how an innovative technology that converts waste products from the corn harvest into renewable biofuels will help the U.S. produce billions of gallons of cellulosic biofuels over the coming decade. It will also stimulate local economies and reduce U.S. dependence on foreign oil.

Mathisen, Todd; Bruch, Don;

2013-05-29

242

A New Biofuels Technology Blooms in Iowa  

ScienceCinema

Cellulosic biofuels made from agricultural waste have caught the attention of many farmers and could be the next revolution in renewable biofuels production. This video shows how an innovative technology that converts waste products from the corn harvest into renewable biofuels will help the U.S. produce billions of gallons of cellulosic biofuels over the coming decade. It will also stimulate local economies and reduce U.S. dependence on foreign oil.

243

A New Biofuels Technology Blooms in Iowa  

SciTech Connect

Cellulosic biofuels made from agricultural waste have caught the attention of many farmers and could be the next revolution in renewable biofuels production. This video shows how an innovative technology that converts waste products from the corn harvest into renewable biofuels will help the U.S. produce billions of gallons of cellulosic biofuels over the coming decade. It will also stimulate local economies and reduce U.S. dependence on foreign oil.

Mathisen, Todd; Bruch, Don

2010-01-01

244

Biofuels: Report to Congress  

EPA Science Inventory

Section 204 of the Energy Independence and Security Act of 2007 (EISA 2007) requires EPA to assess and report to Congress on the impacts to date and likely future impacts of the increased use of biofuels as required by the Clean Air Act, section 211(0). Environmental issues (...

245

Feasibility of filamentous fungi for biofuel production using hydrolysate from dilute sulfuric acid pretreatment of wheat straw  

PubMed Central

Background Lipids produced from filamentous fungi show great promise for biofuel production, but a major limiting factor is the high production cost attributed to feedstock. Lignocellulosic biomass is a suitable feedstock for biofuel production due to its abundance and low value. However, very limited study has been performed on lipid production by culturing oleaginous fungi with lignocellulosic materials. Thus, identification of filamentous fungal strains capable of utilizing lignocellulosic hydrolysates for lipid accumulation is critical to improve the process and reduce the production cost. Results The growth performances of eleven filamentous fungi were investigated when cultured on glucose and xylose. Their dry cell weights, lipid contents and fatty acid profiles were determined. Six fungal strains with high lipid contents were selected to culture with the hydrolysate from dilute sulfuric acid pretreatment of wheat straw. The results showed that all the selected fungal strains were able to grow on both detoxified liquid hydrolysate (DLH) and non-detoxified liquid hydrolysate (NDLH). The highest lipid content of 39.4% was obtained by Mortierella isabellina on NDLH. In addition, NDLH with some precipitate could help M. isabellina form pellets with an average diameter of 0.11?mm. Conclusion This study demonstrated the possibility of fungal lipid production from lignocellulosic biomass. M. isabellina was the best lipid producer grown on lignocellulosic hydrolysates among the tested filamentous fungi, because it could not only accumulate oils with a high content by directly utilizing NDLH to simplify the fermentation process, but also form proper pellets to benefit the downstream harvesting. Considering the yield and cost, fungal lipids from lignocellulosic biomass are promising alternative sources for biodiesel production.

2012-01-01

246

Biofuels: Potential Production Capacity, Effects on Grain and Livestock Sectors, and Implications for Food Prices and Consumers  

Microsoft Academic Search

We examined four evolution paths of the biofuel sector using a partial equilibrium world agricultural sector model in CARD that includes the new RFS in the 2007 EISA, a two-way relationship between fossil energy and biofuel markets, and a new trend toward corn oil extraction in ethanol plants. At one extreme, one scenario eliminates all support to the biofuel sector

Dermot J. Hayes; Bruce A. Babcock; Jacinto F. Fabiosa; Simla Tokgoz; Amani E. Elobeid; Tun-Hsiang Yu; Fengxia Dong; Chad E. Hart; Eddie C. Chavez; Suwen Pan; Miguel A. Carriquiry; Jerome Dumortier

2009-01-01

247

Rapid Manufacturing: The Future of Production Systems  

NSDL National Science Digital Library

Rapid Prototyping is a technology that converts three-dimensional computer models into physical parts typically by building layers upon layer of material. This technology has been serving designers for almost 20 years in support of demonstrating, testing, and confirming their designs early and frequently in the product development process. Increasing interest of designers in Rapid Prototyping (RP) in the last decade has led to development of new technologies and advancements in RP materials. Building a functional part or assembly directly from its CAD (Computer Aided Design) model gave manufacturers the opportunity of rapid and custom production capability of parts such as molds, inserts, tools, subassemblies and even final products. Hence, the term Rapid Manufacturing (RM) has been added to the terminology. It is unlikely that RM will replace mass-manufacturing techniques in the near future due to some constraints. However, for small lot productions, highly complex parts and increased customization demands by customers Rapid Manufacturing may be the answer. Today, more than thirty companies around the world manufacture RP systems with different capacities and features. Rapid Prototyping / Manufacturing system producers utilize different technologies that require different materials. In this environment, manufacturing companies experience serious difficulties in search of appropriate materials and corresponding technologies for their use. This paper is aimed to present background on RP/RM technologies, current application fields of RM, comparison of RM with CNC (Computer Numerical Control) technology, and a critical view of most commonly utilized RM methods. Moreover, emphasis on RP/RM education complements the first portion of the paper with inclusion of Robert Morris University Engineering Department efforts to use RP/RM in engineering curriculum and expand technology awareness among current and prospective engineers.

Czajkiewicz, Zbigniew; Sirinterlikci, Arif; Uslu, Ozden

2012-03-29

248

Engineering an Isoprenoid Pathway in Escherichia coli for Production of 2-Methyl-3-buten-2-ol: A Potential Biofuel.  

PubMed

2-Methyl-3-buten-2-ol (MBO) is a natural volatile 5-carbon alcohol produced by several pine species that have the potential to be used as biofuel. MBO has a high energy content making it superior to ethanol in terms of energy output, and due to its volatility and lower solubility in water, MBO is easier to recover than ethanol. Pine's MBO synthase enzyme utilizes the intermediate dimethylallyl pyrophosphate (DMAPP) produced by the methyl-erythritol-4-phosphate isoprenoid pathway for the production of MBO. In this study, we performed metabolic engineering of Escherichia coli to express an alternate mevalonate dependent pathway for production of DMAPP, along with a codon optimized Pinus sabiniana MBO synthase gene. This heterologous expressed pathway carried out the conversion of an acetyl CoA precursor to DMAPP leading to production of MBO. PMID:24271564

Gupta, Dinesh; Summers, Michael L; Basu, Chhandak

2014-06-01

249

Carbon Cycling from Biofuel Crop Production in the Mid-Continental U. S. Region Predicted from MODIS Satellite Data and Ecosystem Modeling  

NASA Astrophysics Data System (ADS)

The NASA-CASA (Carnegie Ames Stanford Approach) simulation model based on satellite observations of monthly vegetation cover from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate biomass production from croplands across the states of Iowa and Nebraska (United States) over the period 2001-2004. Adjustments for light-use efficiency and water use in biofuel (both corn and perennial grass) crops were carried out across the region, resulting in a new mapping of aboveground and belowground carbon pools based on 500-meter resolution MODIS satellite data. Simulations of plant residue management and soil carbon decomposition were conducted in the NASA-CASA model during and following conversions to biofuel crops to track the fate of carbon pools and the emissions of greenhouse gases. Initial results are being compared to biofuel production reports from southern Iowa for model calibration and validation. The long-term aims of this research are to enhance understanding of the effects of biofuel feedstocks on the biogeochemical cycling of carbon, nitrogen, and water by bringing NASA satellite data sets to bear on the problems of tracking cropland production trends and shifts in different cover areas of native vegetation and biofuel crops.

Hiatt, S.; Potter, C.; Klooster, S.

2008-12-01

250

Forest Products Industry of the Future  

SciTech Connect

Los Alamos Technical Associates, Inc (LATA) conducted an evaluation of the potential impact and value of a portion of the current portfolio of r&d projects supported by the Office of Industrial Technology and the Forest Products Industry of the Future. The mission of the evaluation was to (a) assess the potential impact of the projects to meet the critical goals of the industry as identified in the vision and roadmapping documents. (b) Evaluate the relationship between the current portfolio of projects and the Agenda 202 Implementation Plan. In addition, evaluate the relationship between the portfolio and the newly revised draft technology strategy being created by the industry. (c) Identify areas where current efforts are making significant progress towards meeting industry goals and identify areas where additional work my be required to meet these goals. (d) Make recommendations to the DOE and the Forest Products Industry on possible improvements in the portfolio and in the current methodology that DOE uses to assess potential impacts on its R&D activities.

Los Alamos Technical Associates, Inc

2002-05-01

251

Comparative energetics and kinetics of autotrophic lipid and starch metabolism in chlorophytic microalgae: implications for biomass and biofuel production  

PubMed Central

Due to the growing need to provide alternatives to fossil fuels as efficiently, economically, and sustainably as possible there has been growing interest in improved biofuel production systems. Biofuels produced from microalgae are a particularly attractive option since microalgae have production potentials that exceed the best terrestrial crops by 2 to 10-fold. In addition, autotrophically grown microalgae can capture CO2 from point sources reducing direct atmospheric greenhouse gas emissions. The enhanced biomass production potential of algae is attributed in part to the fact that every cell is photosynthetic. Regardless, overall biological energy capture, conversion, and storage in microalgae are inefficient with less than 8% conversion of solar into chemical energy achieved. In this review, we examine the thermodynamic and kinetic constraints associated with the autotrophic conversion of inorganic carbon into storage carbohydrate and oil, the dominant energy storage products in Chlorophytic microalgae. We discuss how thermodynamic restrictions including the loss of fixed carbon during acetyl CoA synthesis reduce the efficiency of carbon accumulation in lipids. In addition, kinetic limitations, such as the coupling of proton to electron transfer during plastoquinone reduction and oxidation and the slow rates of CO2 fixation by Rubisco reduce photosynthetic efficiency. In some cases, these kinetic limitations have been overcome by massive increases in the numbers of effective catalytic sites, e.g. the high Rubisco levels (mM) in chloroplasts. But in other cases, including the slow rate of plastoquinol oxidation, there has been no compensatory increase in the abundance of catalytically limiting protein complexes. Significantly, we show that the energetic requirements for producing oil and starch relative to the recoverable energy stored in these molecules are very similar on a per carbon basis. Presently, the overall rates of starch and lipid synthesis in microalgae are very poorly characterized. Increased understanding of the kinetic constraints of lipid and starch synthesis, accumulation and turnover would facilitate the design of improved biomass production systems.

2013-01-01

252

Biofuels development and the policy regime.  

PubMed

Any major change to the energy order is certain to provoke both positive and negative societal responses. The current wave of biofuels development ignited controversies that have re-shaped the thinking about their future development. Mistakes were made in the early support for road transport biofuels in Organisation for Economic Co-operation and Development (OECD) countries. This article examines some of the policies that shaped the early development of biofuels and looks to the future. PMID:23174283

Philp, Jim C; Guy, Ken; Ritchie, Rachael J

2013-01-01

253

17 CFR 41.41 - Security futures products accounts.  

Code of Federal Regulations, 2013 CFR

17 Commodity and Securities Exchanges 1 2013-04-01 2013-04-01 false Security futures products accounts. 41.41 Section 41.41 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION SECURITY...

2013-04-01

254

Improving the feasibility of producing biofuels from microalgae using wastewater.  

PubMed

Biofuels have received much attention recently owing to energy consumption and environmental concerns. Despite many of the technologies being technically feasible, the processes are often too costly to be commercially viable. The major stumbling block to full-scale production of algal biofuels is the cost of upstream and downstream processes and environmental impacts such as water footprint and indirect greenhouse gas emissions from chemical nutrient production. The technoeconomics of biofuels production from microalgae is currently unfeasible due to the cost of inputs and productivities achieved. The use of a biorefinery approach sees the production costs reduced greatly due to utilization of waste streams for cultivation and the generation of several potential energy sources and value-added products while offering environmental protection. The use of wastewater as a production media, coupled with CO2 sequestration from flue gas greatly reduces the microalgal cultivation costs. Conversion of residual biomass and by-products, such as glycerol, for fuel production using an integrated approach potentially holds the key to near future commercial implementation of biofuels production. PMID:24350433

Rawat, I; Bhola, V; Kumar, R Ranjith; Bux, F

2013-01-01

255

Glycogen production for biofuels by the euryhaline cyanobacteria Synechococcus sp. strain PCC 7002 from an oceanic environment  

PubMed Central

Background Oxygenic photosynthetic microorganisms such as cyanobacteria and microalgae have attracted attention as an alternative carbon source for the next generation of biofuels. Glycogen abundantly accumulated in cyanobacteria is a promising feedstock which can be converted to ethanol through saccharification and fermentation processes. In addition, the utilization of marine cyanobacteria as a glycogen producer can eliminate the need for a freshwater supply. Synechococcus sp. strain PCC 7002 is a fast-growing marine coastal euryhaline cyanobacteria, however, the glycogen yield has not yet been determined. In the present study, the effects of light intensity, CO2 concentration, and salinity on the cell growth and glycogen content were investigated in order to maximize glycogen production in Synechococcus sp. strain PCC 7002. Results The optimal culture conditions for glycogen production in Synechococcus sp. strain PCC 7002 were investigated. The maximum glycogen production of 3.5 g L?1 for 7 days (a glycogen productivity of 0.5 g L?1 d?1) was obtained under a high light intensity, a high CO2 level, and a nitrogen-depleted condition in brackish water. The glycogen production performance in Synechococcus sp. strain PCC 7002 was the best ever reported in the ?-polyglucan (glycogen or starch) production of cyanobacteria and microalgae. In addition, the robustness of glycogen production in Synechococcus sp. strain PCC 7002 to salinity was evaluated in seawater and freshwater. The peak of glycogen production of Synechococcus sp. strain PCC 7002 in seawater and freshwater were 3.0 and 1.8 g L?1 in 7 days, respectively. Glycogen production in Synechococcus sp. strain PCC 7002 maintained the same level in seawater and half of the level in freshwater compared with the optimal result obtained in brackish water. Conclusions We conclude that Synechococcus sp. strain PCC 7002 has high glycogen production activity and glycogen can be provided from coastal water accompanied by a fluctuation of salinity. This work supports Synechococcus sp. strain PCC 7002 as a promising carbohydrate source for biofuel production.

2014-01-01

256

Method development for the characterization of biofuel intermediate products using gas chromatography with simultaneous mass spectrometric and flame ionization detections.  

PubMed

Accurate analytical methods are required to develop and evaluate the quality of new renewable transportation fuels and intermediate organic liquid products (OLPs). Unfortunately, existing methods developed for the detailed characterization of petroleum products, are not accurate for many of the OLPs generated from non-petroleum feedstocks. In this study, a method was developed and applied to the detailed characterization of complex OLPs formed during triacylglyceride (TG) pyrolysis which is the basis for generating one class of emerging biofuels. This method uses gas chromatography coupled simultaneously with flame ionization and mass spectrometry detectors (GC-FID/MS). The FID provided accurate quantification of carbonaceous species while MS enabled identification of unknown compounds. A programed temperature vaporizer using a 25 °C, 0.1 min, 720 °C min(-1), 350 °C, 5 min temperature program is employed which minimizes compound discrimination better than the more commonly utilized split/splitless injector, as verified with injections at 250 and 350 °C. Two standard mixtures featuring over 150 components are used for accurate identification and a designed calibration standard accounts for compound discrimination at the injector and differing FID responses of various classes of compounds. This new method was used to identify and quantify over 250 species in OLPs generated from canola oil, soybean oil, and canola methyl ester (CME). In addition to hydrocarbons, the method was used to quantify polar (upon derivatization) and unidentified species, plus the unresolved complex mixture that has not typically been determined in previous studies. Repeatability of the analytical method was below 5% RSD for all individual components. Using this method, the mass balance was closed for samples derived from canola and soybean oil but only ca. 77 wt% of the OLP generated from CME could be characterized. The ability to close the mass balance depended on sample origin, demonstrating the need for an accurate quantification method for biofuels at various stages of production. PMID:22245174

S?ávová, Jana; Stahl, Danese C; Seames, Wayne S; Kubátová, Alena

2012-02-10

257

Water use implications of biofuel scenarios  

NASA Astrophysics Data System (ADS)

Existing studies rely upon attributional lifecycle analysis (LCA) approaches to estimate water intensity of biofuels in liters of irrigated/evapotranspiration water consumed for biofuel production. Such approaches can be misleading. From a policy perspective, a better approach is to compare differential water impacts among scenarios on a landscape scale. We address the shortcomings of existing studies by using consequential LCA, and incorporate direct and indirect land use (changes) of biofuel scenarios, marginal vs. average biofuel water use estimates, future climate, and geographic heterogeneity. We use the outputs of a partial equilibrium economic model, climate and soil data, and a process-based crop-soil-climate-water model to estimate differences in green water (GW - directly from precipitation to soil) and blue water (BW - supplied by irrigation) use among three scenarios: (1) business-as-usual (BAU), (2) Renewable Fuels Standard (RFS) mandates, and (3) a national Low Carbon Fuel Standard (LCFS) plus the RFS scenario. We use spatial statistical methods to interpolate key climatic variables using daily climate observations for the contiguous USA. Finally, we use FAO's crop model AquaCrop to estimate the domestic GW and BW impacts of biofuel policies from 2007-2035. We assess the differences among scenarios along the following metrics: (1) crop area expansion at the county level, including prime and marginal lands, (2) crop-specific and overall annual/seasonal water balances including (a) water inflows (irrigation & precipitation), (b) crop-atmosphere interactions: (evaporation & transpiration) and (d) soil-water flows (runoff & soil infiltration), in mm 3 /acre over the relevant time period. The functional unit of analysis is the BW and GW requirements of biofuels (mm3 per Btu biofuel) at the county level. Differential water use impacts among scenarios are a primarily a function of (1) land use conversion, in particular that of formerly uncropped land classes (2) irrigation practices, (3) feedstock water use efficiency, and (4) the longer growing season and a predominance of rainfed cultivation of dedicated biofuel feedstocks. National-level total water use is lowest in the BAU scenario and highest in the RFS2 + LCFS scenario. Figure: Million acres converted to growing miscanthus (top) & switchgrass (bottom) under the RFS + LCFS scenario in 2035. Land use classes are crop pasture (blue), idle cropland (red-purple) & prime cropland (brown).

Teter, J.; Mishra, G. S.; Yeh, S.

2012-12-01

258

Combinatorial design of a highly efficient xylose-utilizing pathway in Saccharomyces cerevisiae for the production of cellulosic biofuels.  

PubMed

Balancing the flux of a heterologous metabolic pathway by tuning the expression and properties of the pathway enzymes is difficult, but it is critical to realizing the full potential of microbial biotechnology. One prominent example is the metabolic engineering of a Saccharomyces cerevisiae strain harboring a heterologous xylose-utilizing pathway for cellulosic-biofuel production, which remains a challenge even after decades of research. Here, we developed a combinatorial pathway-engineering approach to rapidly create a highly efficient xylose-utilizing pathway for ethanol production by exploring various combinations of enzyme homologues with different properties. A library of more than 8,000 xylose utilization pathways was generated using DNA assembler, followed by multitiered screening, which led to the identification of a number of strain-specific combinations of the enzymes for efficient conversion of xylose to ethanol. The balancing of metabolic flux through the xylose utilization pathway was demonstrated by a complete reversal of the major product from xylitol to ethanol with a similar yield and total by-product formation as low as 0.06 g/g xylose without compromising cell growth. The results also suggested that an optimal enzyme combination depends on not only the genotype/phenotype of the host strain, but also the sugar composition of the fermentation medium. This combinatorial approach should be applicable to any heterologous pathway and will be instrumental in the optimization of industrial production of value-added products. PMID:23183982

Kim, Byoungjin; Du, Jing; Eriksen, Dawn T; Zhao, Huimin

2013-02-01

259

Combinatorial Design of a Highly Efficient Xylose-Utilizing Pathway in Saccharomyces cerevisiae for the Production of Cellulosic Biofuels  

PubMed Central

Balancing the flux of a heterologous metabolic pathway by tuning the expression and properties of the pathway enzymes is difficult, but it is critical to realizing the full potential of microbial biotechnology. One prominent example is the metabolic engineering of a Saccharomyces cerevisiae strain harboring a heterologous xylose-utilizing pathway for cellulosic-biofuel production, which remains a challenge even after decades of research. Here, we developed a combinatorial pathway-engineering approach to rapidly create a highly efficient xylose-utilizing pathway for ethanol production by exploring various combinations of enzyme homologues with different properties. A library of more than 8,000 xylose utilization pathways was generated using DNA assembler, followed by multitiered screening, which led to the identification of a number of strain-specific combinations of the enzymes for efficient conversion of xylose to ethanol. The balancing of metabolic flux through the xylose utilization pathway was demonstrated by a complete reversal of the major product from xylitol to ethanol with a similar yield and total by-product formation as low as 0.06 g/g xylose without compromising cell growth. The results also suggested that an optimal enzyme combination depends on not only the genotype/phenotype of the host strain, but also the sugar composition of the fermentation medium. This combinatorial approach should be applicable to any heterologous pathway and will be instrumental in the optimization of industrial production of value-added products.

Kim, Byoungjin; Du, Jing; Eriksen, Dawn T.

2013-01-01

260

Fatty acid from the renewable sources: a promising feedstock for the production of biofuels and biobased chemicals.  

PubMed

With the depletion of the nonrenewable petrochemical resources and the increasing concerns of environmental pollution globally, biofuels and biobased chemicals produced from the renewable resources appear to be of great strategic significance. The present review described the progress in the biosynthesis of fatty acid and its derivatives from renewable biomass and emphasized the importance of fatty acid serving as the platform chemical and feedstock for a variety of chemicals. Due to the low efficient conversions of lignocellulosic biomass or carbon dioxide to fatty acid, we also put forward that rational strategies for the production of fatty acid and its derivatives should further derive from the consideration of whole bioprocess (pretreatment, saccharification, fermentation, separation), multiscale analysis and interdisciplinary combinations (omics, kinetics, metabolic engineering, synthetic biology, fermentation and so on). PMID:24361277

Liu, Hui; Cheng, Tao; Xian, Mo; Cao, Yujin; Fang, Fang; Zou, Huibin

2014-01-01

261

Favouring butyrate production for a new generation biofuel by acidogenic glucose fermentation using cells immobilised on ?-alumina.  

PubMed

The effect of ?-alumina as a fermentation advancing tool and as carrier for culture immobilisation, regarding VFAs and ethanol production during acidogenic fermentation of glucose, was examined at various process conditions (sugar concentration, pH) and operation modes (continuous with and without effluent recirculation and batch). The results showed that at high initial pH (8.9) the continuous acidogenic fermentation of glucose led to high yields of VFAs and favoured the accumulation of butyric acid. The batch process on the other hand at pH 6.5, favoured the ethanol-type fermentation. The results indicate that in the frame of technology development for new generation biofuels, using ?-alumina as a process advancing tool at optimum process conditions (pH, initial glucose concentration and mode of operation), the produced VFAs profile and ethanol concentration may be manipulated. PMID:24690582

Syngiridis, Kostas; Bekatorou, Argyro; Kandylis, Panagiotis; Larroche, Christian; Kanellaki, Maria; Koutinas, Athanasios A

2014-06-01

262

Biological nitrogen fixation in sugar cane: A key to energetically viable biofuel production  

SciTech Connect

The advantages of producing biofuels to replace fossil energy sources are derived from the fact that the energy accumulated in the biomass in captured directly from photosynthesis and is thus renewable, and that the cycle of carbon dioxide fixation by the crop, followed by burning of the fuel makes no overall contribution to atmospheric CO{sub 2} or, consequently, to global warming. However, these advantages are negated if large quantities of fossil fuels need to be used to grow or process the biofuel crop. In this regard, the Brazilian bioethanol program, based on the fermentation/distillation of sugar cane juice, is particularly favorable, not only because the crop is principally hand harvested, but also because of the low nitrogen fertilizer use on sugar cane in Brazil. Recent {sup 15}N and N balance studies have shown that in some Brazilian cane varieties, high yields are possible without N fertilization because the plants are able to obtain large contributions of nitrogen from plant-associated biological N{sub 2} fixation (BNF). The N{sub 2}-fixing acid-tolerant bacterium Acetobacter diazotrophicus was first found to occur within roots, stems, and leaves of sugar cane. Subsequently, two species of Herbaspirillum also have been found to occur within the interior of all sugar cane tissues. The discovery of these, and other N{sub 2}-fixing bacteria that survive poorly in soil but thrive within plant tissue (endophytic bacteria), may account for the high BNF contributions observed in sugar cane. Further study of this system should allow the gradual elimination of N fertilizer use on sugar cane, at least in Brazil, and opens up the possibility of the extension of this efficient N{sub 2}-fixing system to cereal and other crops with consequent immense potential benefits to tropical agriculture. 44 refs., 9 figs., 4 tabs.

Boddey, R.M. [Centro Nacional de Pesquisa de Agrobiologia, Rio de Janeiro (Brazil)

1995-05-01

263

Tailoring next-generation biofuels and their combustion in next-generation engines.  

SciTech Connect

Increasing energy costs, the dependence on foreign oil supplies, and environmental concerns have emphasized the need to produce sustainable renewable fuels and chemicals. The strategy for producing next-generation biofuels must include efficient processes for biomass conversion to liquid fuels and the fuels must be compatible with current and future engines. Unfortunately, biofuel development generally takes place without any consideration of combustion characteristics, and combustion scientists typically measure biofuels properties without any feedback to the production design. We seek to optimize the fuel/engine system by bringing combustion performance, specifically for advanced next-generation engines, into the development of novel biosynthetic fuel pathways. Here we report an innovative coupling of combustion chemistry, from fundamentals to engine measurements, to the optimization of fuel production using metabolic engineering. We have established the necessary connections among the fundamental chemistry, engine science, and synthetic biology for fuel production, building a powerful framework for co-development of engines and biofuels.

Gladden, John Michael; Wu, Weihua; Taatjes, Craig A.; Scheer, Adam Michael; Turner, Kevin.; Yu, Eizadora T.; O'Bryan, Greg; Powell, Amy Jo; Gao, Connie W. [Massachusetts Institute of Technology, Cambridge, MA] [Massachusetts Institute of Technology, Cambridge, MA

2013-11-01

264

Shifting Lands: Exploring Kansas Farmer Decision-Making in an Era of Climate Change and Biofuels Production  

NASA Astrophysics Data System (ADS)

While farming has been the subject of frequent critical analysis with respect to its environmental impacts, including its greenhouse gas emissions, there has been relatively little consideration of the potentially positive role of agriculture in responding to a future greatly influenced by climate change. One possible realm for agriculture to contribute successfully to this future is through biofuels cultivation. This paper uses the state of Kansas as an example to examine factors that are influencing farmer decision-making during a time of heightened debates about climate and energy. Drawing on interviews with key informants and Kansas farmers, we apply and refine a conceptual model for understanding farmer decisions. We find that farmers have largely positive perceptions of the natural environment. Climate change, especially, is not a salient concern at this time. Factors that appear most likely to influence farmer decisions to adopt a new practice include the relative advantage of that practice and the ability to learn about and discuss it through existing social networks. Successful policy incentives must provide farmers with a continued sense of both independence and contribution to greater societal good.

White, Stacey Swearingen; Selfa, Theresa

2013-02-01

265

Shifting lands: exploring Kansas farmer decision-making in an era of climate change and biofuels production.  

PubMed

While farming has been the subject of frequent critical analysis with respect to its environmental impacts, including its greenhouse gas emissions, there has been relatively little consideration of the potentially positive role of agriculture in responding to a future greatly influenced by climate change. One possible realm for agriculture to contribute successfully to this future is through biofuels cultivation. This paper uses the state of Kansas as an example to examine factors that are influencing farmer decision-making during a time of heightened debates about climate and energy. Drawing on interviews with key informants and Kansas farmers, we apply and refine a conceptual model for understanding farmer decisions. We find that farmers have largely positive perceptions of the natural environment. Climate change, especially, is not a salient concern at this time. Factors that appear most likely to influence farmer decisions to adopt a new practice include the relative advantage of that practice and the ability to learn about and discuss it through existing social networks. Successful policy incentives must provide farmers with a continued sense of both independence and contribution to greater societal good. PMID:23229828

White, Stacey Swearingen; Selfa, Theresa

2013-02-01

266

Effects of fatty acid activation on photosynthetic production of fatty acid-based biofuels in Synechocystis sp. PCC6803  

PubMed Central

Background Direct conversion of solar energy and carbon dioxide to drop in fuel molecules in a single biological system can be achieved from fatty acid-based biofuels such as fatty alcohols and alkanes. These molecules have similar properties to fossil fuels but can be produced by photosynthetic cyanobacteria. Results Synechocystis sp. PCC6803 mutant strains containing either overexpression or deletion of the slr1609 gene, which encodes an acyl-ACP synthetase (AAS), have been constructed. The complete segregation and deletion in all mutant strains was confirmed by PCR analysis. Blocking fatty acid activation by deleting slr1609 gene in wild-type Synechocystis sp. PCC6803 led to a doubling of the amount of free fatty acids and a decrease of alkane production by up to 90 percent. Overexpression of slr1609 gene in the wild-type Synechocystis sp. PCC6803 had no effect on the production of either free fatty acids or alkanes. Overexpression or deletion of slr1609 gene in the Synechocystis sp. PCC6803 mutant strain with the capability of making fatty alcohols by genetically introducing fatty acyl-CoA reductase respectively enhanced or reduced fatty alcohol production by 60 percent. Conclusions Fatty acid activation functionalized by the slr1609 gene is metabolically crucial for biosynthesis of fatty acid derivatives in Synechocystis sp. PCC6803. It is necessary but not sufficient for efficient production of alkanes. Fatty alcohol production can be significantly improved by the overexpression of slr1609 gene.

2012-01-01

267

The Role of Social Constructions and Biophysical Attributes of the Environment in Decision-Making in the Context of Biofuels and Rubber Production Partnership Regimes in Upland Philippines  

NASA Astrophysics Data System (ADS)

Burgeoning attention in biofuels and natural rubber has spurred interest among governments and private companies in integrating marginalized communities into global commodity markets. Upland farmers from diverse cultural backgrounds and biophysical settings today are deciding whether to agree with partnership proposals from governments and private firms to grow biofuels and natural rubber. In this paper, I examine whether upland farmers' socio-environmental constructions (evaluative beliefs, place satisfaction, and ecological worldviews) and the actual biophysical attributes (land cover and soil types) of upland environments, respectively, function as significant predictors of the intent and decisions of indigenous and non-indigenous farmers to cooperate with government and private actors to establish certain biofuel crops and natural rubber production systems in Palawan, Philippines. Drawing from ethnography and statistical analysis of household surveys, I propose that social constructions and the biophysical attributes of the environment are closely related with each other and in turn both influence individual decision-making behavior in resource-based production partnership regimes. This has significant implications on the resilience of socio-ecological systems, particularly agro-ecosystems, as certain upland farmers prefer to engage in intensive, monocrop production of biofuels and natural rubber on relatively more biodiverse areas, such as secondary forests and traditional shifting cultivation lands. The study aims to advance new institutional theories of resource management, particularly Ostrom's Institutional Analysis and Development and Socio-Ecological Systems frameworks, and scholarship on environmental decision-making in the context of collective action.

Montefrio, M. F.

2012-12-01

268

Biofuel impacts on water.  

SciTech Connect

Sandia National Laboratories and General Motors Global Energy Systems team conducted a joint biofuels systems analysis project from March to November 2008. The purpose of this study was to assess the feasibility, implications, limitations, and enablers of large-scale production of biofuels. 90 billion gallons of ethanol (the energy equivalent of approximately 60 billion gallons of gasoline) per year by 2030 was chosen as the book-end target to understand an aggressive deployment. Since previous studies have addressed the potential of biomass but not the supply chain rollout needed to achieve large production targets, the focus of this study was on a comprehensive systems understanding the evolution of the full supply chain and key interdependencies over time. The supply chain components examined in this study included agricultural land use changes, production of biomass feedstocks, storage and transportation of these feedstocks, construction of conversion plants, conversion of feedstocks to ethanol at these plants, transportation of ethanol and blending with gasoline, and distribution to retail outlets. To support this analysis, we developed a 'Seed to Station' system dynamics model (Biofuels Deployment Model - BDM) to explore the feasibility of meeting specified ethanol production targets. The focus of this report is water and its linkage to broad scale biofuel deployment.

Tidwell, Vincent Carroll; Malczynski, Leonard A.; Sun, Amy Cha-Tien

2011-01-01

269

Sugar industry in China: R & D and policy initiatives to meet sugar and biofuel demand of future  

Microsoft Academic Search

The sugar industry in China is becoming increasingly important both domestically and internationally because of its rapid\\u000a development. Significant progress has been achieved not only in sugar production, but also in the integrated utilization,\\u000a developments such as productions of sugar-based products and cane by-products, and environment-friendly management of vinasse.\\u000a Production of luquid fuel (ethanol) from sugarcane is also gaining much

Yang-Rui Li; Yuan-An Wei

2006-01-01

270

Use of algae as biofuel sources  

Microsoft Academic Search

The aim of this study is to investigate the algae production technologies such as open, closed and hybrid systems, production costs, and algal energy conversions. Liquid biofuels are alternative fuels promoted with potential to reduce dependence on fossil fuel imports. Biofuels production costs can vary widely by feedstock, conversion process, scale of production and region. Algae will become the most

Ayhan Demirbas

2010-01-01

271

Engineered Respiro-Fermentative Metabolism for the Production of Biofuels and Biochemicals from Fatty Acid-Rich Feedstocks? †  

PubMed Central

Although lignocellulosic sugars have been proposed as the primary feedstock for the biological production of renewable fuels and chemicals, the availability of fatty acid (FA)-rich feedstocks and recent progress in the development of oil-accumulating organisms make FAs an attractive alternative. In addition to their abundance, the metabolism of FAs is very efficient and could support product yields significantly higher than those obtained from lignocellulosic sugars. However, FAs are metabolized only under respiratory conditions, a metabolic mode that does not support the synthesis of fermentation products. In the work reported here we engineered several native and heterologous fermentative pathways to function in Escherichia coli under aerobic conditions, thus creating a respiro-fermentative metabolic mode that enables the efficient synthesis of fuels and chemicals from FAs. Representative biofuels (ethanol and butanol) and biochemicals (acetate, acetone, isopropanol, succinate, and propionate) were chosen as target products to illustrate the feasibility of the proposed platform. The yields of ethanol, acetate, and acetone in the engineered strains exceeded those reported in the literature for their production from sugars, and in the cases of ethanol and acetate they also surpassed the maximum theoretical values that can be achieved from lignocellulosic sugars. Butanol was produced at yields and titers that were between 2- and 3-fold higher than those reported for its production from sugars in previously engineered microorganisms. Moreover, our work demonstrates production of propionate, a compound previously thought to be synthesized only by propionibacteria, in E. coli. Finally, the synthesis of isopropanol and succinate was also demonstrated. The work reported here represents the first effort toward engineering microorganisms for the conversion of FAs to the aforementioned products.

Dellomonaco, Clementina; Rivera, Carlos; Campbell, Paul; Gonzalez, Ramon

2010-01-01

272

Fuel from wastewater : harnessing a potential energy source in Canada through the co-location of algae biofuel production to sources of effluent, heat and CO2.  

SciTech Connect

Sandia National Laboratories is collaborating with the National Research Council (NRC) Canada and the National Renewable Energy Laboratory (NREL) to develop a decision-support model that will evaluate the tradeoffs associated with high-latitude algae biofuel production co-located with wastewater, CO2, and waste heat. This project helps Canada meet its goal of diversifying fuel sources with algae-based biofuels. The biofuel production will provide a wide range of benefits including wastewater treatment, CO2 reuse and reduction of demand for fossil-based fuels. The higher energy density in algae-based fuels gives them an advantage over crop-based biofuels as the 'production' footprint required is much less, resulting in less water consumed and little, if any conversion of agricultural land from food to fuel production. Besides being a potential source for liquid fuel, algae have the potential to be used to generate electricity through the burning of dried biomass, or anaerobically digested to generate methane for electricity production. Co-locating algae production with waste streams may be crucial for making algae an economically valuable fuel source, and will certainly improve its overall ecological sustainability. The modeling process will address these questions, and others that are important to the use of water for energy production: What are the locations where all resources are co-located, and what volumes of algal biomass and oil can be produced there? In locations where co-location does not occur, what resources should be transported, and how far, while maintaining economic viability? This work is being funded through the U.S. Department of Energy (DOE) Biomass Program Office of Energy Efficiency and Renewable Energy, and is part of a larger collaborative effort that includes sampling, strain isolation, strain characterization and cultivation being performed by the NREL and Canada's NRC. Results from the NREL / NRC collaboration including specific productivities of selected algal strains will eventually be incorporated into this model.

Passell, Howard David; Whalen, Jake (SmartWhale Consulting, Dartmouth, NS, CA); Pienkos, Philip P. (National Renewable Energy Laboratory, Golden, CO); O'Leary, Stephen J. (National Research Council Canada, Institute for Marine Biosciences, Halifax, NS, CA); Roach, Jesse Dillon; Moreland, Barbara D.; Klise, Geoffrey Taylor

2010-12-01

273

Local bioprospecting for high-lipid producing microalgal strains to be grown on concentrated municipal wastewater for biofuel production.  

PubMed

Mass cultivation of microalgae for biofuel production depends heavily on the performance of the microalgae strains used. In this study, 60 algae-like microorganisms collected from different sampling sites in Minnesota were examined using multi-step screening and acclimation procedures to select high-lipid producing facultative heterotrophic microalgae strains capable of growing on concentrated municipal wastewater (CMW) for simultaneous energy crop production and wastewater treatment. Twenty-seven facultative heterotrophic microalgae strains were found, among which 17 strains were proved to be tolerant to CMW. These 17 top-performing strains were identified through morphological observation and DNA sequencing as Chlorella sp., Heynigia sp., Hindakia sp., Micractinium sp., and Scenedesmus sp. Five strains were chosen for other studies because of their ability to adapt to CMW, high growth rates (0.455-0.498 d(-1)) and higher lipid productivities (74.5-77.8 mg L(-1)d(-1)). These strains are considered highly promising compared with other strains reported in the literature. PMID:21546246

Zhou, Wenguang; Li, Yecong; Min, Min; Hu, Bing; Chen, Paul; Ruan, Roger

2011-07-01

274

Third Generation Biofuels via Direct Cellulose Fermentation  

PubMed Central

Consolidated bioprocessing (CBP) is a system in which cellulase production, substrate hydrolysis, and fermentation are accomplished in a single process step by cellulolytic microorganisms. CBP offers the potential for lower biofuel production costs due to simpler feedstock processing, lower energy inputs, and higher conversion efficiencies than separate hydrolysis and fermentation processes, and is an economically attractive near-term goal for “third generation” biofuel production. In this review article, production of third generation biofuels from cellulosic feedstocks will be addressed in respect to the metabolism of cellulolytic bacteria and the development of strategies to increase biofuel yields through metabolic engineering.

Carere, Carlo R.; Sparling, Richard; Cicek, Nazim; Levin, David B.

2008-01-01

275

Midwest U.S. Landscape Change to 2020 Driven by Biofuel Mandates  

EPA Science Inventory

Meeting future biofuel targets set by the 2007 Energy Independence and Security Act (EISA), without a loss of animal feedstock or grain for human consumption, will require a substantial increase in production of corn. The Midwest, which has the highest overall crop production ap...

276

Agriculture - Sustainable biofuels Redux  

SciTech Connect

Last May's passage of the 2008 Farm Bill raises the stakes for biofuel sustainability: A substantial subsidy for the production of cellulosic ethanol starts the United States again down a path with uncertain environmental consequences. This time, however, the subsidy is for both the refiners ($1.01 per gallon) and the growers ($45 per ton of biomass), which will rapidly accelerate adoption and place hard-to-manage pressures on efforts to design and implement sustainable production practices - as will a 2007 legislative mandate for 16 billion gallons of cellulosic ethanol per year by 2022. Similar directives elsewhere, e.g., the European Union's mandate that 10% of all transport fuel in Europe be from renewable sources by 2020, make this a global issue. The European Union's current reconsideration of this target places even more emphasis on cellulosic feedstocks (1). The need for knowledge- and science-based policy is urgent. Biofuel sustainability has environmental, economic, and social facets that all interconnect. Tradeoffs among them vary widely by types of fuels and where they are grown and, thus, need to be explicitly considered by using a framework that allows the outcomes of alternative systems to be consistently evaluated and compared. A cellulosic biofuels industry could have many positive social and environmental attributes, but it could also suffer from many of the sustainability issues that hobble grain-based biofuels, if not implemented the right way.

Robertson, G. Phillip [W.K. Kellogg Biological Station and Great Lakes Bioenergy Research; Dale, Virginia H [ORNL; Doering, Otto C. [Purdue University; Hamburg, Steven P [Brown University; Melillo, Jerry M [ORNL; Wander, Michele M [University of Illinois, Urbana-Champaign; Parton, William [Colorado State University, Fort Collins

2008-10-01

277

Predicting Agricultural Management Influence on Long-Term Soil Organic Carbon Dynamics: Implications for Biofuel Production  

SciTech Connect

Long-term field experiments (LTE) are ideal for predicting the influence of agricultural management on soil organic carbon (SOC) dynamics and examining biofuel crop residue removal policy questions. Our objectives were (i) to simulate SOC dynamics in LTE soils under various climates, crop rotations, fertilizer or organic amendments, and crop residue managements using the CQESTR model and (ii) to predict the potential of no-tillage (NT) management to maintain SOC stocks while removing crop residue. Classical LTEs at Champaign, IL (1876), Columbia, MO (1888), Lethbridge, AB (1911), Breton, AB (1930), and Pendleton, OR (1931) were selected for their documented history of management practice and periodic soil organic matter (SOM) measurements. Management practices ranged from monoculture to 2- or 3-yr crop rotations, manure, no fertilizer or fertilizer additions, and crop residue returned, burned, or harvested. Measured and CQESTR predicted SOC stocks under diverse agronomic practices, mean annual temperature (2.1 19 C), precipitation (402 973 mm), and SOC (5.89 33.58 g SOC kg 1) at the LTE sites were significantly related (r 2 = 0.94, n = 186, P < 0.0001) with a slope not significantly different than 1. The simulation results indicated that the quantities of crop residue that can be sustainably harvested without jeopardizing SOC stocks were influenced by initial SOC stocks, crop rotation intensity, tillage practices, crop yield, and climate. Manure or a cover crop/intensified crop rotation under NT are options to mitigate loss of crop residue C, as using fertilizer alone is insufficient to overcome residue removal impact on SOC stocks

Gollany, H. T. [USDA ARS; Rickman, R. W. [USDA ARS; Albrecht, S. L. [USDA ARS; Liang, Y. [University of Arkansas; Kang, Shujiang [ORNL; Machado, S. [Oregon State University, Corvallis

2011-01-01

278

Transcriptome sequencing and annotation of the microalgae Dunaliella tertiolecta: Pathway description and gene discovery for production of next-generation biofuels  

PubMed Central

Background Biodiesel or ethanol derived from lipids or starch produced by microalgae may overcome many of the sustainability challenges previously ascribed to petroleum-based fuels and first generation plant-based biofuels. The paucity of microalgae genome sequences, however, limits gene-based biofuel feedstock optimization studies. Here we describe the sequencing and de novo transcriptome assembly for the non-model microalgae species, Dunaliella tertiolecta, and identify pathways and genes of importance related to biofuel production. Results Next generation DNA pyrosequencing technology applied to D. tertiolecta transcripts produced 1,363,336 high quality reads with an average length of 400 bases. Following quality and size trimming, ~ 45% of the high quality reads were assembled into 33,307 isotigs with a 31-fold coverage and 376,482 singletons. Assembled sequences and singletons were subjected to BLAST similarity searches and annotated with Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) orthology (KO) identifiers. These analyses identified the majority of lipid and starch biosynthesis and catabolism pathways in D. tertiolecta. Conclusions The construction of metabolic pathways involved in the biosynthesis and catabolism of fatty acids, triacylglycrols, and starch in D. tertiolecta as well as the assembled transcriptome provide a foundation for the molecular genetics and functional genomics required to direct metabolic engineering efforts that seek to enhance the quantity and character of microalgae-based biofuel feedstock.

2011-01-01

279

Treatment with algae extracts promotes flocculation, and enhances growth and neutral lipid content in Nannochloropsis oculata--a candidate for biofuel production.  

PubMed

Marine microalgae represent a potentially valuable feedstock for biofuel production; however, large-scale production is not yet economically viable. Optimisation of productivity and lipid yields is required and the cost of biomass harvesting and dewatering must be significantly reduced. Microalgae produce a wide variety of biologically active metabolites, many of which are involved in inter- and intra-specific interactions (the so-called infochemicals). The majority of infochemicals remain unidentified or uncharacterised. Here, we apply known and candidate (undefined extracts) infochemicals as a potential means to manipulate the growth and lipid content of Nannochloropsis oculata-a prospective species for biofuel production. Five known infochemicals (?-cyclocitral, trans,trans-2,4-decadienal, hydrogen peroxide, norharman and tryptamine) and crude extracts prepared from Skeletonema marinoi and Dunaliella salina cultures at different growth stages were assayed for impacts on N. oculata over 24 h. The neutral lipid content of N. oculata increased significantly with exposure to three infochemicals (?-cyclocitral, decadienal and norharman); however the effective concentrations affected a significant decrease in growth. Exposure to particular crude extracts significantly increased both growth and neutral lipid levels. In addition, water-soluble extracts of senescent S. marinoi cultures induced a degree of flocculation in the N. oculata. These preliminary results indicate that artificial manipulation of N. oculata cultures by application of algae infochemicals could provide a valuable tool towards achieving economically viable large-scale algae biofuel production. PMID:22527265

Taylor, Rebecca L; Rand, Jonathan D; Caldwell, Gary S

2012-12-01

280

Enhancement of BODIPY505/515 lipid fluorescence method for applications in biofuel-directed microalgae production.  

PubMed

This paper describes a microalgal cell lipid fluorescence enhancement method using BODIPY(505/515), which can be used to screen for lipids in wild-type microalgae and to monitor lipid content within microalgae production processes to determine optimal harvesting time. The study was based on four microalgae species (Dunaliella teteriolecta, Tetraselmis suecica, Nannochloropsis oculata, and Nannochloris atomus) selected because of their inherent high lipid content. An extended analysis was carried out with N. oculata due to the depressed fluorescence observed when compared with the other experimental strains. BODIPY(505/515) lipid fluorescence was determined for two solvent pre-treatment methods (DMSO and glycerol) and four staining condition parameters (analysis time, staining temperature, dye concentration, and algal cell concentration). It was found that lipid fluorescence of thick cell-walled microalgae, such as N. oculata, is significantly enhanced by both the pre-treatment methods and staining condition parameters, thereby significantly enhancing lipid fluorescence by ca. 800 times the base autofluorescence. The lipid fluorescence enhancement method provides a quick and simple index for in vivo Flow Cytometry quantification of total lipid contents for purposes of species screening or whole culture monitoring in biofuel-directed microalgae production. PMID:22521923

Brennan, Liam; Blanco Fernández, Alfonso; Mostaert, Anika S; Owende, Philip

2012-08-01

281

[Tobacco--a source of biofuels].  

PubMed

One of the concepts of global protection of environment is to reduce greenhouse gas emissions, mainly carbon dioxide, into the atmosphere by replacing fossil fuels by the so-called biofuels, which can be obtained from cultivated plants or any plant waste biomass. Currently applied industrial technologies allow the production of biofuels to receive ethanol, mostly from the reserve carbohydrates of sugar cane and corn as well as biodiesel from oil, mainly from rapeseed or oil palm. Tobacco, which provides a high biomass, can be used to produce biogas, bioethanol and biodiesel. The latter derived from oil from seeds and leaves of tobacco has proved useful for driving cars. Modest oil content in tobacco leaves can be increased by the expression of foreign genes encoding its biosynthesis. Promising future source of biofuels is a waste plant biomass consisting mainly of cell walls, which can be subjected to the degradation to produce sugars suitable for fermentation and the production of bioethanol. A number of enzymes needed for efficient degradation of plant cell walls can be produced using recombinant DNA technology in a variety of plants, particularly in chloroplasts of tobacco. PMID:23421113

Budzianowska, Anna; Budzianowski, Jaromir

2012-01-01

282

At a tipping point? How the debate on biofuel standards sparks innovative ideas for the general future of standardisation and certification schemes  

Microsoft Academic Search

Consumer demand for environmentally and socially responsible products is the driving force behind the expansion of competing certification systems. Paradoxically, this has led to an increasingly crowded marketplace for labels and confusion among stakeholders such as producers, retailers and buyers, rather than providing clear and reliable product information as intended. The situation has sparked a debate about the future of

Timo Kaphengst; Mandy S. Ma; Stephanie Schlegel

2009-01-01

283

Mobility chains analysis of technologies for passenger cars and light duty vehicles fueled with biofuels : application of the Greet model to project the role of biomass in America's energy future (RBAEF) project.  

SciTech Connect

The Role of Biomass in America's Energy Future (RBAEF) is a multi-institution, multiple-sponsor research project. The primary focus of the project is to analyze and assess the potential of transportation fuels derived from cellulosic biomass in the years 2015 to 2030. For this project, researchers at Dartmouth College and Princeton University designed and simulated an advanced fermentation process to produce fuel ethanol/protein, a thermochemical process to produce Fischer-Tropsch diesel (FTD) and dimethyl ether (DME), and a combined heat and power plant to co-produce steam and electricity using the ASPEN Plus{trademark} model. With support from the U.S. Department of Energy (DOE), Argonne National Laboratory (ANL) conducted, for the RBAEF project, a mobility chains or well-to-wheels (WTW) analysis using the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model developed at ANL. The mobility chains analysis was intended to estimate the energy consumption and emissions associated with the use of different production biofuels in light-duty vehicle technologies.

Wu, M.; Wu, Y.; Wang, M; Energy Systems

2008-01-31

284

Global Trends on the Processing of Biofuels  

Microsoft Academic Search

The aim of the present paper is to investigate bio-fuels produced from biomass materials by thermochemical and biochemical methods and the utilization trends of the products in the world. Bio-fuels are liquid or gaseous fuels made from plant matter and residues, such as agricultural crops, municipal wastes and agricultural and forestry by-products. Liquid bio-fuels being considered world over fall into

Mustafa Balat

2008-01-01

285

Algae as a sustainable energy source for biofuel production in Iran: A case study  

Microsoft Academic Search

Algae can be converted directly into energy, such as biodiesel, bioethanol and biomethanol and therefore can be a source of renewable energy. There is a growing interest for biodiesel production from algae because of its higher yield non-edible oil production and its fast growth that does not compete for land with food production. About 50% of algae weight is oil

Gholamhassan Najafi; Barat Ghobadian; Talal F. Yusaf

2011-01-01

286

Introducing Liquid Biofuels into the GTAP Data Base  

Microsoft Academic Search

Production of liquid biofuels has rapidly increased around the world in recent years. Biofuel production, by its nature, can affect the economy and environment of many countries in different ways. Global Computable General Equilibrium (CGE) analysis is an appropriate approach to study the widespread socio-economic and environmental impacts of bioenergy production. An appropriate benchmark data base including an independent biofuel

Farzad Taheripour; Dileep K. Birur; Thomas W. Hertel; Wallace E. Tyner

2007-01-01

287

Future prospects for production of methanol and hydrogen from biomass  

Microsoft Academic Search

Technical and economic prospects of the future production of methanol and hydrogen from biomass have been evaluated. A technology review, including promising future components, was made, resulting in a set of promising conversion concepts. Flowsheeting models were made to analyse the technical performance. Results were used for economic evaluations. Overall energy efficiencies are around 55% HHV for methanol and around

Carlo N Hamelinck

2002-01-01

288

Biorefineries for biofuel upgrading: A critical review  

Microsoft Academic Search

This study reviews the biofuel valorization facilities as well as the future importance of biorefineries. Biomass can be converted into useful biofuels and bio-chemicals via biomass upgrading and biorefinery technologies. A biorefinery is a facility that integrates biomass conversion processes to produce fuels, power, and chemicals from biomass. Biomass upgrading processes include fractionation, liquefaction, pyrolysis, hydrolysis, fermentation, and gasification. Upgraded

M. Fatih Demirbas

2009-01-01

289

Water Requirements for Future Energy Production in California.  

National Technical Information Service (NTIS)

This assessment estimates the impact of future national energy development on water resources. Energy development would include various types of electric power plants, production of synthetic fuels, coal and uranium mining, oil and gas extraction, and oth...

J. A. Sathaye R. L. Ritschard

1977-01-01

290

Genetic Engineering of Allergens: Future Therapeutic Products  

Microsoft Academic Search

Genetic engineering of allergens for specific immunotherapy should aim at the production of modified molecules with reduced IgE-binding epitopes (hypoallergens), while preserving structural motifs necessary for T cell recognition (T cell epitopes) and for induction of IgG antibodies reactive with the natural allergen (blocking antibodies). Common approaches for engineering of hypoallergens usually require knowledge of T and B cell epitopes

Fátima Ferreira; Michael Wallner; Heimo Breiteneder; Arnulf Hartl; Josef Thalhamer; Christof Ebner

2002-01-01

291

Future demand of petroleum products in India  

Microsoft Academic Search

This paper examines the long-run equilibrium relationship between total petroleum products consumption and economic growth in India for the period 1970–1971 to 2001–2002 using cointegration and error-correction modeling approach. Augmented Dickey–Fuller tests reveal that both the series, after logarithmic transformation, are non-stationary and individually integrated of order one. The empirical results suggest that the series are cointegrated. The ‘long-term demand

Sajal Ghosh

2006-01-01

292

Carbon Cycling from Biofuel Crop Production in the Mid-Continental U. S. Region Predicted from MODIS Satellite Data and Ecosystem Modeling  

Microsoft Academic Search

The NASA-CASA (Carnegie Ames Stanford Approach) simulation model based on satellite observations of monthly vegetation cover from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate biomass production from croplands across the states of Iowa and Nebraska (United States) over the period 2001-2004. Adjustments for light-use efficiency and water use in biofuel (both corn and perennial grass) crops were

S. Hiatt; C. Potter; S. Klooster

2008-01-01

293

Agave proves to be a low recalcitrant lignocellulosic feedstock for biofuels production on semi-arid lands  

PubMed Central

Background Agave, which is well known for tequila and other liquor production in Mexico, has recently gained attention because of its attractive potential to launch sustainable bioenergy feedstock solutions for semi-arid and arid lands. It was previously found that agave cell walls contain low lignin and relatively diverse non-cellulosic polysaccharides, suggesting unique recalcitrant features when compared to conventional C4 and C3 plants. Results Here, we report sugar release data from fungal enzymatic hydrolysis of non-pretreated and hydrothermally pretreated biomass that shows agave to be much less recalcitrant to deconstruction than poplar or switchgrass. In fact, non-pretreated agave has a sugar release five to eight times greater than that of poplar wood and switchgrass . Meanwhile, state of the art techniques including glycome profiling, nuclear magnetic resonance (NMR), Simon’s Stain, confocal laser scanning microscopy and so forth, were applied to measure interactions of non-cellulosic wall components, cell wall hydrophilicity, and enzyme accessibility to identify key structural features that make agave cell walls less resistant to biological deconstruction when compared to poplar and switchgrass. Conclusions This study systematically evaluated the recalcitrant features of agave plants towards biofuels applications. The results show that not only does agave present great promise for feeding biorefineries on semi-arid and arid lands, but also show the value of studying agave’s low recalcitrance for developments in improving cellulosic energy crops.

2014-01-01

294

Phylogenomic Study of Lipid Genes Involved in Microalgal Biofuel Production--Candidate Gene Mining and Metabolic Pathway Analyses  

PubMed Central

Optimizing microalgal biofuel production using metabolic engineering tools requires an in-depth understanding of the structure-function relationship of genes involved in lipid biosynthetic pathway. In the present study, genome-wide identification and characterization of 398 putative genes involved in lipid biosynthesis in Arabidopsis thaliana Chlamydomonas reinhardtii, Volvox carteri, Ostreococcus lucimarinus, Ostreococcus tauri and Cyanidioschyzon merolae was undertaken on the basis of their conserved motif/domain organization and phylogenetic profile. The results indicated that the core lipid metabolic pathways in all the species are carried out by a comparable number of orthologous proteins. Although the fundamental gene organizations were observed to be invariantly conserved between microalgae and Arabidopsis genome, with increased order of genome complexity there seems to be an association with more number of genes involved in triacylglycerol (TAG) biosynthesis and catabolism. Further, phylogenomic analysis of the genes provided insights into the molecular evolution of lipid biosynthetic pathway in microalgae and confirm the close evolutionary proximity between the Streptophyte and Chlorophyte lineages. Together, these studies will improve our understanding of the global lipid metabolic pathway and contribute to the engineering of regulatory networks of algal strains for higher accumulation of oil.

Misra, Namrata; Panda, Prasanna Kumar; Parida, Bikram Kumar; Mishra, Barada Kanta

2012-01-01

295

Modification of Lignin by Protein Cross-linking to Facilitate Production of Biofuels From Poplar  

SciTech Connect

The limited supply of fossil fuels and the associated environmental issues associated with their utilization has resulted in much effort put forth to promote renewable resources of energy. Switching to renewable fuels for energy will allow us to become carbon neutral by recycling carbon from plants and reduce carbon from dioxide emissions, which could potentially reduce global warming in future generations and generate new industries with exciting new technologies.

Tien, Ming [The Pennsylvania State University] [The Pennsylvania State University

2013-04-22

296

Generating Phenotypic Diversity in a Fungal Biocatalyst to Investigate Alcohol Stress Tolerance Encountered during Microbial Cellulosic Biofuel Production  

PubMed Central

Consolidated bioprocessing (CBP) of lignocellulosic biomass offers an alternative route to renewable energy. The crop pathogen Fusarium oxysporum is a promising fungal biocatalyst because of its broad host range and innate ability to co-saccharify and ferment lignocellulose to bioethanol. A major challenge for cellulolytic CBP-enabling microbes is alcohol inhibition. This research tested the hypothesis that Agrobacterium tumefaciens - mediated transformation (ATMT) could be exploited as a tool to generate phenotypic diversity in F. oxysporum to investigate alcohol stress tolerance encountered during CBP. A random mutagenesis library of gene disruption transformants (n=1,563) was constructed and screened for alcohol tolerance in order to isolate alcohol sensitive or tolerant phenotypes. Following three rounds of screening, exposure of select transformants to 6% ethanol and 0.75% n-butanol resulted respectively in increased (?11.74%) and decreased (?43.01%) growth compared to the wild –type (WT). Principal component analysis (PCA) quantified the level of phenotypic diversity across the population of genetically transformed individuals and isolated candidate strains for analysis. Characterisation of one strain, Tr. 259, ascertained a reduced growth phenotype under alcohol stress relative to WT and indicated the disruption of a coding region homologous to a putative sugar transporter (FOXG_09625). Quantitative PCR (RT-PCR) showed FOXG_09625 was differentially expressed in Tr. 259 compared to WT during alcohol-induced stress (P<0.05). Phylogenetic analysis of putative sugar transporters suggests diverse functional roles in F. oxysporum and other filamentous fungi compared to yeast for which sugar transporters form part of a relatively conserved family. This study has confirmed the potential of ATMT coupled with a phenotypic screening program to select for genetic variation induced in response to alcohol stress. This research represents a first step in the investigation of alcohol tolerance in F. oxysporum and has resulted in the identification of several novel strains, which will be of benefit to future biofuel research.

Hennessy, Rosanna C.; Doohan, Fiona; Mullins, Ewen

2013-01-01

297

Energy Efficiency Analysis: Biomass-to-Wheel Efficiency Related with Biofuels Production, Fuel Distribution, and Powertrain Systems  

PubMed Central

Background Energy efficiency analysis for different biomass-utilization scenarios would help make more informed decisions for developing future biomass-based transportation systems. Diverse biofuels produced from biomass include cellulosic ethanol, butanol, fatty acid ethyl esters, methane, hydrogen, methanol, dimethyether, Fischer-Tropsch diesel, and bioelectricity; the respective powertrain systems include internal combustion engine (ICE) vehicles, hybrid electric vehicles based on gasoline or diesel ICEs, hydrogen fuel cell vehicles, sugar fuel cell vehicles (SFCV), and battery electric vehicles (BEV). Methodology/Principal Findings We conducted a simple, straightforward, and transparent biomass-to-wheel (BTW) analysis including three separate conversion elements -- biomass-to-fuel conversion, fuel transport and distribution, and respective powertrain systems. BTW efficiency is a ratio of the kinetic energy of an automobile's wheels to the chemical energy of delivered biomass just before entering biorefineries. Up to 13 scenarios were analyzed and compared to a base line case – corn ethanol/ICE. This analysis suggests that BEV, whose electricity is generated from stationary fuel cells, and SFCV, based on a hydrogen fuel cell vehicle with an on-board sugar-to-hydrogen bioreformer, would have the highest BTW efficiencies, nearly four times that of ethanol-ICE. Significance In the long term, a small fraction of the annual US biomass (e.g., 7.1%, or 700 million tons of biomass) would be sufficient to meet 100% of light-duty passenger vehicle fuel needs (i.e., 150 billion gallons of gasoline/ethanol per year), through up to four-fold enhanced BTW efficiencies by using SFCV or BEV. SFCV would have several advantages over BEV: much higher energy storage densities, faster refilling rates, better safety, and less environmental burdens.

Huang, Wei-Dong; Zhang, Y-H Percival

2011-01-01

298

Generating phenotypic diversity in a fungal biocatalyst to investigate alcohol stress tolerance encountered during microbial cellulosic biofuel production.  

PubMed

Consolidated bioprocessing (CBP) of lignocellulosic biomass offers an alternative route to renewable energy. The crop pathogen Fusarium oxysporum is a promising fungal biocatalyst because of its broad host range and innate ability to co-saccharify and ferment lignocellulose to bioethanol. A major challenge for cellulolytic CBP-enabling microbes is alcohol inhibition. This research tested the hypothesis that Agrobacterium tumefaciens--mediated transformation (ATMT) could be exploited as a tool to generate phenotypic diversity in F. oxysporum to investigate alcohol stress tolerance encountered during CBP. A random mutagenesis library of gene disruption transformants (n=1,563) was constructed and screened for alcohol tolerance in order to isolate alcohol sensitive or tolerant phenotypes. Following three rounds of screening, exposure of select transformants to 6% ethanol and 0.75% n-butanol resulted respectively in increased (? 11.74%) and decreased (? 43.01%) growth compared to the wild -type (WT). Principal component analysis (PCA) quantified the level of phenotypic diversity across the population of genetically transformed individuals and isolated candidate strains for analysis. Characterisation of one strain, Tr. 259, ascertained a reduced growth phenotype under alcohol stress relative to WT and indicated the disruption of a coding region homologous to a putative sugar transporter (FOXG_09625). Quantitative PCR (RT-PCR) showed FOXG_09625 was differentially expressed in Tr. 259 compared to WT during alcohol-induced stress (P<0.05). Phylogenetic analysis of putative sugar transporters suggests diverse functional roles in F. oxysporum and other filamentous fungi compared to yeast for which sugar transporters form part of a relatively conserved family. This study has confirmed the potential of ATMT coupled with a phenotypic screening program to select for genetic variation induced in response to alcohol stress. This research represents a first step in the investigation of alcohol tolerance in F. oxysporum and has resulted in the identification of several novel strains, which will be of benefit to future biofuel research. PMID:24147009

Hennessy, Rosanna C; Doohan, Fiona; Mullins, Ewen

2013-01-01

299

Global Potential of Rice Husk as a Renewable Feedstock for Ethanol Biofuel Production  

Microsoft Academic Search

The production of ethanol for the energy market has traditionally been from corn and sugar cane biomass. The use of such biomass\\u000a as energy feedstocks has recently been criticised as ill-fated due to competitive threat against food supplies. At the same\\u000a time, ethanol production from cellulosic biomass is becoming increasingly popular. In this paper, we analyse rice husk (RH)\\u000a as

Ali Abbas; Santosh Ansumali

2010-01-01

300

Fibre optic grating sensors for biofuels  

NASA Astrophysics Data System (ADS)

Biofuels will have more intense impact on the energetic grid of the planet, because known fossil fuels reserves are being exhausted. The biofuel production relies on the transformation process of some organic material in the desired hydrocarbon product. Because of the natural characteristics of the related processes, fibre optic sensors appear to be adequate candidates to be used.

Muller, M.; Fabris, J. L.; Kalinowski, H. J.

2010-09-01

301

Biofuels from algae for sustainable development  

Microsoft Academic Search

Microalgae are photosynthetic microorganisms that can produce lipids, proteins and carbohydrates in large amounts over short periods of time. These products can be processed into both biofuels and useful chemicals. Two algae samples (Cladophora fracta and Chlorella protothecoid) were studied for biofuel production. Microalgae appear to be the only source of renewable biodiesel that is capable of meeting the global

M. Fatih Demirbas

2011-01-01

302

The Future of Butyric Acid in Industry  

PubMed Central

In this paper, the different applications of butyric acid and its current and future production status are highlighted, with a particular emphasis on the biofuels industry. As such, this paper discusses different issues regarding butyric acid fermentations and provides suggestions for future improvements and their approaches.

Dwidar, Mohammed; Park, Jae-Yeon; Mitchell, Robert J.; Sang, Byoung-In

2012-01-01

303

Boundless Biofuels? Between Environmental Sustainability and Vulnerability  

Microsoft Academic Search

Biofuels currently appear to be one of the major controversies in the agriculture\\/environment nexus, not unlike genetically modified organisms. While some countries (such as Brazil) have for quite some time supported successful large-scale programmes to improve the production and consumption of biofuels, policy-makers and research institutions in most developed and developing countries have only recently turned their attention to biofuels.

Arthur P. J. Mol

2007-01-01

304

Time reducing process for biofuel production from non edible oil assisted by ultrasonication.  

PubMed

Limited resources of conventional fuels such as petrodiesel have led to the search for alternative fuels. Various convention batch/continuous processes for the biodiesel production have been developed before the recent year. All processes are time consuming with high labor cost. Thus, we need a new process for biodiesel production which reduces the reaction time and production cost as well as save the energy. In this work, ultrasonic assisted transesterification of Jatrophacurcas oil is carried out in the presence of methanol and potassium hydroxide (KOH) as catalyst, keeping the molar ratio of oil to alcohol 1:5, catalyst concentration 0.75wt% of oil, ultrasonic amplitude 50% and pulse 0.3 cycle, 7min reaction time under atmospheric condition. Ultrasonic mixing has increased the rate of transesterification reaction as compare to the mechanical mixing. PMID:24792785

Kumar, Gajendra; Kumar, Dharmendra; Johari, Rajeev

2014-09-01

305

Arid Lands Biofuel  

NASA Astrophysics Data System (ADS)

Dependence on imported petroleum, as well as consequences from burning fossil fuels, has increased the demand for biofuel sources in the United States. Competition between food crops and biofuel crops has been an increasing concern, however, since it has the potential to raise prices for US beef and grain products due to land and resource competition. Biofuel crops that can be grown on land not suitable for food crops are thus attractive, but also need to produce biofuels in a financially sustainable manner. In the intermountain west of Nevada, biofuel crops need to survive on low-organic soils with limited precipitation when grown in areas that are not competing with food and feed. The plants must also yield an oil content sufficiently high to allow economically viable fuel production, including growing and harvesting the crop as well as converting the hydrocarbons into a liquid fuel. Gumweed (Grindelia squarrosa) currently appears to satisfy all of these requirements and is commonly observed throughout the west. The plant favors dry, sandy soils and is most commonly found on roadsides and other freshly disturbed land. A warm season biennial, the gumweed plant is part of the sunflower family and normally grows 2-4 feet high with numerous yellow flowers and curly leaves. The gumweed plant contains a large store of diterpene resins—most abundantly grindelic acid— similar to the saps found on pine trees that are used to make inks and adhesives. The dry weight harvest on the experimental field is 5130 lbs/acre. Whole plant biomass yields between 11-15% (average 13%) biocrude when subjected to acetone extraction whereas the buds alone contains up to a maximum of 35% biocrude when harvested in 'white milky' stage. The extract is then converted to basic form (sodium grindelate) followed by extraction of nonpolar constituents (mostly terpenes) with hexane and extracted back to ethyl acetate in acidified condition. Ethyl acetate is removed under vacuum to leave a dark colored viscous gum. At this point, when methylated and the mixture analyzed by gas chromatography, grindelic acid methyl ester composes approximately 60-80% of the hydrocarbons present which is the actual available portion for biodiesel. Based on two years of crop data, we can say that we can produce in between 85-126 gallons of biofuel per acre of land. While agronomic issues remain still to be solved, crops can be grown, harvested and extracted using conventional methods. Further research is being undertaken to select optimal strains of gumweed, as well as methods of conversion of grindelic acid to a diesel fuel directly.

Neupane, B. P.

2013-05-01

306

A spatially explicit techno-economic model of bioenergy and biofuels production in California  

Microsoft Academic Search

This study presents a spatially explicit techno-economic Bioenergy Siting Model (BSM) of the bioenergy production system in California. The model describes the bioenergy system in terms of facility siting and size, conversion technology, feedstock profile, and feedstock supply chain configuration for the year 2015. The BSM expands upon previous bioenergy siting work by optimizing the system using spatially explicit feedstock

P. W. Tittmann; N. C. Parker; Q. J. Hart; B. M. Jenkins

2010-01-01

307

Thermodynamic analysis of lignocellulosic biofuel production via a biochemical process: Guiding technology selection and research focus  

Microsoft Academic Search

The aim of this paper is to present an exergy analysis of bioethanol production process from lignocellulosic feedstock via a biochemical process to asses the overall thermodynamic efficiency and identify the main loss processes. The thermodynamic efficiency of the biochemical process was found to be 35% and the major inefficiencies of this process were identified as: the combustion of lignin

M. Imroz Sohel; Michael W. Jack

2011-01-01

308

An integrated renewable energy park approach for algal biofuel production in United States  

Microsoft Academic Search

Algal biomass provides viable third generation feedstock for liquid transportation fuel that does not compete with food crops for cropland. However, fossil energy inputs and intensive water usage diminishes the positive aspects of algal energy production. An integrated renewable energy park (IREP) approach is proposed for aligning renewable energy industries in resource-specific regions in United States for synergistic electricity and

Bobban Subhadra; Mark Edwards

2010-01-01

309

Identification and thermochemical analysis of high-lignin feedstocks for biofuel and biochemical production  

PubMed Central

Background Lignin is a highly abundant biopolymer synthesized by plants as a complex component of plant secondary cell walls. Efforts to utilize lignin-based bioproducts are needed. Results Herein we identify and characterize the composition and pyrolytic deconstruction characteristics of high-lignin feedstocks. Feedstocks displaying the highest levels of lignin were identified as drupe endocarp biomass arising as agricultural waste from horticultural crops. By performing pyrolysis coupled to gas chromatography-mass spectrometry, we characterized lignin-derived deconstruction products from endocarp biomass and compared these with switchgrass. By comparing individual pyrolytic products, we document higher amounts of acetic acid, 1-hydroxy-2-propanone, acetone and furfural in switchgrass compared to endocarp tissue, which is consistent with high holocellulose relative to lignin. By contrast, greater yields of lignin-based pyrolytic products such as phenol, 2-methoxyphenol, 2-methylphenol, 2-methoxy-4-methylphenol and 4-ethyl-2-methoxyphenol arising from drupe endocarp tissue are documented. Conclusions Differences in product yield, thermal decomposition rates and molecular species distribution among the feedstocks illustrate the potential of high-lignin endocarp feedstocks to generate valuable chemicals by thermochemical deconstruction.

2011-01-01

310

Microbial production of sabinene--a new terpene-based precursor of advanced biofuel  

PubMed Central

Background Sabinene, one kind of monoterpene, accumulated limitedly in natural organisms, is being explored as a potential component for the next generation of aircraft fuels. And demand for advanced fuels impels us to develop biosynthetic routes for the production of sabinene from renewable sugar. Results In this study, sabinene was significantly produced by assembling a biosynthetic pathway using the methylerythritol 4-phosphate (MEP) or heterologous mevalonate (MVA) pathway combining the GPP and sabinene synthase genes in an engineered Escherichia coli strain. Subsequently, the culture medium and process conditions were optimized to enhance sabinene production with a maximum titer of 82.18 mg/L. Finally, the fed-batch fermentation of sabinene was evaluated using the optimized culture medium and process conditions, which reached a maximum concentration of 2.65 g/L with an average productivity of 0.018 g h-1 g-1 dry cells, and the conversion efficiency of glycerol to sabinene (gram to gram) reached 3.49%. Conclusions This is the first report of microbial synthesis of sabinene using an engineered E. coli strain with the renewable carbon source as feedstock. Therefore, a green and sustainable production strategy has been established for sabinene.

2014-01-01

311

Integration of first and second generation biofuels: fermentative hydrogen production from wheat grain and straw.  

PubMed

Integrating of lignocellulose-based and starch-rich biomass-based hydrogen production was investigated by mixing wheat straw hydrolysate with a wheat grain hydrolysate for improved fermentation. Enzymatic pretreatment and hydrolysis of wheat grains led to a hydrolysate with a sugar concentration of 93.4 g/L, while dilute-acid pretreatment and enzymatic hydrolysis of wheat straw led to a hydrolysate with sugar concentration 23.0 g/L. Wheat grain hydrolysate was not suitable for hydrogen production by the extreme thermophilic bacterium Caldicellulosiruptor saccharolyticus at glucose concentrations of 10 g/L or higher, and wheat straw hydrolysate showed good fermentability at total sugar concentrations of up to 10 g/L. The mixed hydrolysates showed good fermentability at the highest tested sugar concentration of 20 g/L, with a hydrogen production of 82-97% of that of the control with pure sugars. Mixing wheat grain hydrolysate with wheat straw hydrolysate would be beneficial for fermentative hydrogen production in a biorefinery. PMID:23196256

Panagiotopoulos, I A; Bakker, R R; de Vrije, T; Claassen, P A M; Koukios, E G

2013-01-01

312

Accumulation characteristics of soluble algal products (SAP) by a freshwater microalga Scenedesmus sp. LX1 during batch cultivation for biofuel production.  

PubMed

Algae cultivation is the essential basis for microalgal biofuel production. Soluble algal products (SAP) are significant obstacle to large-scale, high-cell-density cultivation processes. SAP accumulation during batch cultivation of Scenedesmus sp. LX1 (a unique strain accumulating lipid substantially while growing fast under low-nutrient conditions) with different initial nitrogen concentrations (7.4-34.0mgNL(-1)) was investigated. The SAP content varied in the range of 3.4-17.4mgDOCL(-1) at stationary phase, with average yield per cell of 0.5-2.5pgDOCcell(-1). High SAP accumulation up to 15.2-17.4mgDOCL(-1) were observed with initial nitrogen above 20.2mgNL(-1). The maximum SAP production rate per unit culture volume (r(SAP)) was 2.6mgDOC(Ld)(-1) and that per cell (?(SAP)) was 1.5pgDOC(celld)(-1). The r(SAP) increased with cell growth rate and decreased with cell density linearly. The SAP accumulation was majorly due to the release of growth-associated products. PMID:22322147

Yu, Yin; Hu, Hong-Ying; Li, Xin; Wu, Yin-Hu; Zhang, Xue; Jia, Sheng-Lan

2012-04-01

313

Bioprocessing for biofuels.  

PubMed

While engineering of new biofuels pathways into microbial hosts has received considerable attention, innovations in bioprocessing are required for commercialization of both conventional and next-generation fuels. For ethanol and butanol, reducing energy costs for product recovery remains a challenge. Fuels produced from heterologous aerobic pathways in yeast and bacteria require control of aeration and cooling at large scales. Converting lignocellulosic biomass to sugars for fuels production requires effective biomass pretreatment to increase surface area, decrystallize cellulose and facilitate enzymatic hydrolysis. Effective means to recover microalgae and extract their intracellular lipids remains a practical and economic bottleneck in algal biodiesel production. PMID:22033175

Blanch, Harvey W

2012-06-01

314

Regional Impacts of Miscanthus Biofuel Feedstock Production on the Hydrologic Cycle  

NASA Astrophysics Data System (ADS)

Socio-economic and scientific interest toward the use of renewable energy to offset fossil fuel dependence and greenhouse gas emissions is increasing. Currently, the majority of the US renewable energy production is focused on replacing gasoline with corn ethanol. In 2008, 18% of the US corn yield was used to displace ~5% of US gasoline consumption. This represents progress toward meeting the goals of offsetting 30% of liquid fossil fuel consumption by 2030 as established by the US government in the Advanced Energy Initiative (AEI). However, a growing body of research indicates that it may not be beneficial or even possible for corn ethanol alone to meet the AEI goals. Highly productive bioenergy feedstocks requiring fewer inputs such as Miscanthus x Giganteus (Miscanthus) are ideal candidates, relative to maize, to provide a renewable and sustainable alternative to fossil fuel. It is anticipated that Miscanthus is likely to have minimal environmental impacts and could be potentially beneficial to the environment. In order to meet the AEI goals, Miscanthus production on the scale of 1x10<6> ha would be needed. Before this level of production occurs, uncertainty over the environmental impacts of large-scale implementation should be addressed particularly with regards to the hydrologic cycle. We calibrated and evaluated a process-based terrestrial ecosystem model, Agro-IBIS (Integrated Biosphere Simulator, agricultural version), to simulate the impacts of land-use-change from current land-use practices to Miscanthus production on the hydrologic cycle. Simulations for the Midwestern US (0.5°grid cell resolution) were generated using the same climate forcing for current land cover and additional scenarios where Miscanthus was planted in varying densities (10%, 25%, 50%, 75%, and 100%). Analyses indicate that for most of the Midwestern US, large increases in evapotranspiration (~100 to 250 mm/yr) and decreases in drainage (~ -100 to -250 mm/yr) occur when high densities (75-100%) of Miscanthus replace the existing land cover. Analyses of lower densities (10-25%) indicate little to no changes in the same hydrologic cycle components, suggesting that hydrologic impacts could be minimized if Miscanthus production density is moderated.

Vanloocke, A. D.; Twine, T. E.; Bernacchi, C.

2009-12-01

315

Lipid production for biofuels from hydrolyzate of waste activated sludge by heterotrophic Chlorella protothecoides.  

PubMed

Microalga Chlorella protothecoides can accumulate high proportion of lipids during the heterotrophic growth with glucose as the carbon source. However, its commercial application is restricted due to the high cost of the carbon source. In this study, the wasted activated sludge (WAS) was hydrolyzed after ultrasonic pre-treatment and the hydrolyzate obtained was used as an alternative carbon source for algal biomass and biodiesel production. The results indicate that C. protothecoides can proliferate in the WAS hydrolyzate and accumulate biolipid. The final lipid content of the culture fed with the hydrolyzate was 21.5±1.44% (weight percent) after 156 h cultivation in flasks and the maximum biomass obtained was 0.5 g L(-1). Acetic acid and isovaleric acid were favorable carbon sources for cell growth. The soluble microbial products (SMP) presents in the hydrolyzate can also be used as a carbon source for cell growth. PMID:23856018

Wen, Qinxue; Chen, Zhiqiang; Li, Pengfei; Duan, Ran; Ren, Nanqi

2013-09-01

316

Biofuels from waste fish oil pyrolysis: Continuous production in a pilot plant  

Microsoft Academic Search

Fast pyrolysis of waste fish oil was performed in a continuous pyrolysis pilot plant. The experiment was carried out under steady-state conditions in which 10kg of biomass was added at a feed rate of 3.2kgh?1. A bio-oil yield of 72–73% was obtained with a controlled reaction temperature of 525°C. The bio-oil was distilled to obtain purified products with boiling ranges

V. R. Wiggers; A. Wisniewski Jr.; L. A. S. Madureira; A. A. Chivanga Barros; H. F. Meier

2009-01-01

317

Energy resources' utilization in organic and conventional vineyards: Energy flow, greenhouse gas emissions and biofuel production  

Microsoft Academic Search

An energy analysis, in conventional and organic vineyards, combined with ethanol production and greenhouse gas emissions, is useful in evaluating present situation and deciding best management strategies. The objective of this study was to evaluate the differences in the energy flow between organic and conventional vineyards in three locations, to calculate CO2, CH4 and N2O-emissions based on the used fossil

Stefanos E. Kavargiris; Andreas P. Mamolos; Constantinos A. Tsatsarelis; Anna E. Nikolaidou; Kiriaki L. Kalburtji

2009-01-01

318

LIQUID BIOFUEL PRODUCTION FROM NON-FOOD BIOMASS VIA HIGH TEMPERATURE STEAM ELECTROLYSIS  

Microsoft Academic Search

Bio-Syntrolysis is a hybrid energy process that enables production of synthetic liquid fuels that are compatible with the existing conventional liquid transportation fuels infrastructure. Using biomass as a renewable carbon source, and supplemental hydrogen from high-temperature steam electrolysis (HTSE), bio-syntrolysis has the potential to provide a significant alternative petroleum source that could reduce US dependence on imported oil. Combining hydrogen

G. L. Hawkes; J. E. OBrien; M. G. McKellar

2011-01-01

319

PRODUCTION OF BIOFUEL FROM SOFT SHELL OF PISTACHIO (PISTACIA VERA L.)  

Microsoft Academic Search

Soft shell of pistachio (Pistacia veraL.) pyrolysis experiments were performed in a fixed-bed reactor to produce bio-oil. The effects of temperature, heating rate, and sweep gas (N2) flow rates on the yields and compositions of products were investigated. Pyrolysis runs were performed using reactor temperatures between 350° and 500°C with heating rates of 15° and 50°C\\/min. Nitrogen flow rates varied

?lknur Demiral; Nurdilek Gülmezo?lu Atilgan; Sevgi ?ensöz

2008-01-01

320

Assessment of a dry and a wet route for the production of biofuels from microalgae: energy balance analysis.  

PubMed

In this study, the energy balance of two microalgae-to-biofuel concepts, one via a so called "dry route" (oil extraction from dried algae) and one via a "wet route" (oil extraction in the water phase), are assessed. Both routes are intended to convert the chemical energy contained in the microalgae into high-value biofuels with minimal fossil energy consumption. The analysis shows that the drying process in the dry route and the oil extraction process in the wet route consume a significant amount of energy. By coupling waste heat from a nearby power plant to the process, the energy balance can be improved and a potential fossil energy ratio (FER) up to 2.38 and 1.82 can be reached for the dry and wet route, respectively. The results indicate that based on current available technologies, the dry route has higher FER and the wet route has more potential in producing high valuable biofuels. PMID:21334889

Xu, Lixian; Wim Brilman, Derk W F; Withag, Jan A M; Brem, Gerrit; Kersten, Sascha

2011-04-01

321

Kinetic studies on fermentative production of biofuel from synthesis gas using Clostridium ljungdahlii.  

PubMed

The intrinsic growth, substrate uptake, and product formation biokinetic parameters were obtained for the anaerobic bacterium, Clostridium ljungdahlii, grown on synthesis gas in various pressurized batch bioreactors. A dual-substrate growth kinetic model using Luong for CO and Monod for H2 was used to describe the growth kinetics of the bacterium on these substrates. The maximum specific growth rate (?(max) = 0.195 h(-1)) and Monod constants for CO (K s,CO = 0.855?atm) and H2 (K(s,H2) = 0.412?atm) were obtained. This model also accommodated the CO inhibitory effects on cell growth at high CO partial pressures, where no growth was apparent at high dissolved CO tensions (P(CO)(?) > 0.743 atm). The Volterra model, Andrews, and modified Gompertz were, respectively, adopted to describe the cell growth, substrate uptake rate, and product formation. The maximum specific CO uptake rate (q(max) = 34.364?mmol/g cell/h), CO inhibition constant (K(I) = 0.601 atm), and maximum rate of ethanol (R(max) = 0.172 mmol/L/h at P(CO) = 0.598 atm) and acetate (R(max) = 0.096 mmol/L/h at P(CO) = 0.539 atm) production were determined from the applied models. PMID:24672390

Mohammadi, Maedeh; Mohamed, Abdul Rahman; Najafpour, Ghasem D; Younesi, Habibollah; Uzir, Mohamad Hekarl

2014-01-01

322

Kinetic Studies on Fermentative Production of Biofuel from Synthesis Gas Using Clostridium ljungdahlii  

PubMed Central

The intrinsic growth, substrate uptake, and product formation biokinetic parameters were obtained for the anaerobic bacterium, Clostridium ljungdahlii, grown on synthesis gas in various pressurized batch bioreactors. A dual-substrate growth kinetic model using Luong for CO and Monod for H2 was used to describe the growth kinetics of the bacterium on these substrates. The maximum specific growth rate (?max = 0.195?h?1) and Monod constants for CO (Ks,CO = 0.855?atm) and H2 (Ks,H2 = 0.412?atm) were obtained. This model also accommodated the CO inhibitory effects on cell growth at high CO partial pressures, where no growth was apparent at high dissolved CO tensions (PCO? > 0.743?atm). The Volterra model, Andrews, and modified Gompertz were, respectively, adopted to describe the cell growth, substrate uptake rate, and product formation. The maximum specific CO uptake rate (qmax = 34.364?mmol/gcell/h), CO inhibition constant (KI = 0.601?atm), and maximum rate of ethanol (Rmax = 0.172?mmol/L/h at PCO = 0.598?atm) and acetate (Rmax = 0.096?mmol/L/h at PCO = 0.539?atm) production were determined from the applied models.

Mohamed, Abdul Rahman; Najafpour, Ghasem D.; Younesi, Habibollah; Uzir, Mohamad Hekarl

2014-01-01

323

Vertical Integration of Biomass Saccharification of Enzymes for Sustainable Cellulosic Biofuel Production in a Biorefinery  

SciTech Connect

Lignocellulosic biomass is the most abundant, least expensive renewable natural biological resource for the production of biobased products and bioenergy is important for the sustainable development of human civilization in 21st century. For making the fermentable sugars from lignocellulosic biomass, a reduction in cellulase production cost, an improvement in cellulase performance, and an increase in sugar yields are all vital to reduce the processing costs of biorefineries. Improvements in specific cellulase activities for non-complexed cellulase mixtures can be implemented through cellulase engineering based on rational design or directed evolution for each cellulase component enzyme, as well as on the reconstitution of cellulase components. In this paper, we will provide DSM's efforts in cellulase research and developments and focus on limitations. Cellulase improvement strategies based on directed evolution using screening on relevant substrates, screening for higher thermal tolerance based on activity screening approaches such as continuous culture using insoluble cellulosic substrates as a powerful selection tool for enriching beneficial cellulase mutants from the large library. We will illustrate why and how thermostable cellulases are vital for economic delivery of bioproducts from cellulosic biomass using biochemical conversion approach.

Manoj Kumar, PhD

2011-05-09

324

Synergetic sustainability enhancement via current biofuel infrastructure: waste-to-energy concept for biodiesel production.  

PubMed

The concept of waste-to-energy (WtE) with regards to the utilization of byproducts from the bioethanol industry (e.g., distiller's dried grain with solubles: DDGS) was employed to enhance the renewability of biodiesel, which would be an initiative stage of a biorefinery due to the conjunction between bioethanol and biodiesel. For example, DDGS is a strong candidate for use as a biodiesel feedstock due to the tremendous amount that is regularly generated. On the basis of an estimation of possible lipid recovery from DDGS, ?30% of the biodiesel feedstock demand in 2010 could be supported by the total DDGS generation in the same year. Considering the future expansion of the bioethanol industry up to 2020, the possible lipid recovery from DDGS would provide more than 6 times the biodiesel feedstock demand in 2010. In order to enhance the renewability of biodiesel, the transformation of lipid extracted from DDGS into fatty acid ethyl ester (FAEE) via a noncatalytic transesterification reaction under ambient pressure was investigated in this work. The newly introduced method reported here enables the combination of the esterification of free fatty acids (FFAs) and the transesterification of triglycerides into a single step. This was achieved in the presence of a porous material (i.e., charcoal), and the optimal conditions for transformation into biodiesel via this noncatalytic method were assessed at the fundamental level. PMID:23410120

Kwon, Eilhann; Yi, Haakrho; Jeon, Young Jae

2013-03-19

325

Understanding cost drivers and economic potential of two variants of ionic liquid pretreatment for cellulosic biofuel production  

PubMed Central

Background Ionic liquid (IL) pretreatment could enable an economically viable route to produce biofuels by providing efficient means to extract sugars and lignin from lignocellulosic biomass. However, to realize this, novel IL-based processes need to be developed in order to minimize the overall production costs and accelerate commercial viability. In this study, two variants of IL-based processes are considered: one based on complete removal of the IL prior to hydrolysis using a water-wash (WW) step and the other based on a “one-pot” (OP) process that does not require IL removal prior to saccharification. Detailed techno-economic analysis (TEA) of these two routes was carried out to understand the cost drivers, economic potential (minimum ethanol selling price, MESP), and relative merits and challenges of each route. Results At high biomass loading (50%), both routes exhibited comparable economic performance with an MESP of $6.3/gal. With the possible advances identified (reduced water or acid/base consumption, improved conversion in pretreatment, and lignin valorization), the MESP could be reduced to around $3/gal ($3.2 in the WW route and $2.8 in the OP route). Conclusions It was found that, to be competitive at industrial scale, lowered cost of ILs used and higher biomass loadings (50%) are essential for both routes, and in particular for the OP route. Overall, while the economic potential of both routes appears to be comparable at higher biomass loadings, the OP route showed the benefit of lower water consumption at the plant level, an important cost and sustainability consideration for biorefineries.

2014-01-01

326

Changes in the Diversity of Soil Arbuscular Mycorrhizal Fungi after Cultivation for Biofuel Production in a Guantanamo (Cuba) Tropical System  

PubMed Central

The arbuscular mycorrhizal fungi (AMF) are a key, integral component of the stability, sustainability and functioning of ecosystems. In this study, we characterised the AMF biodiversity in a native vegetation soil and in a soil cultivated with Jatropha curcas or Ricinus communis, in a tropical system in Guantanamo (Cuba), in order to verify if a change of land use to biofuel plant production had any effect on the AMF communities. We also asses whether some soil properties related with the soil fertility (total N, Organic C, microbial biomass C, aggregate stability percentage, pH and electrical conductivity) were changed with the cultivation of both crop species. The AM fungal small sub-unit (SSU) rRNA genes were subjected to PCR, cloning, sequencing and phylogenetic analyses. Twenty AM fungal sequence types were identified: 19 belong to the Glomeraceae and one to the Paraglomeraceae. Two AMF sequence types related to cultured AMF species (Glo G3 for Glomus sinuosum and Glo G6 for Glomus intraradices-G. fasciculatum-G. irregulare) did not occur in the soil cultivated with J. curcas and R. communis. The soil properties (total N, Organic C and microbial biomass C) were higher in the soil cultivated with the two plant species. The diversity of the AMF community decreased in the soil of both crops, with respect to the native vegetation soil, and varied significantly depending on the crop species planted. Thus, R. communis soil showed higher AMF diversity than J. curcas soil. In conclusion, R. communis could be more suitable for the long-term conservation and sustainable management of these tropical ecosytems.

Alguacil, Maria del Mar; Torrecillas, Emma; Hernandez, Guillermina; Roldan, Antonio

2012-01-01

327

Microalgae digestate effluent as a growth medium for Tetraselmis sp. in the production of biofuels.  

PubMed

This study investigated an alternative nutrient source arising from anaerobically digested Tetraselmis sp. effluent (MDE) as a nutrient feed stock to form a closed loop nutrient system. To determine MDE suitability the following factors were observed: growth, lipid content, and the bacterial diversity. MDE was diluted according to the concentration of NH4(+) content (20, 40, 60, 80mg/L) and compared against F/2 medium a standard medium for Tetraselmis sp. The growth rate on the MDE medium was not as rapid as the F/2 medium and the less diluted MDE correlated (R(2)) with lower total lipid contents (R(2), 0.927), additionally acyl carrier proteins (ACP) gene expression rates displayed lower gene expression within MDE treatments. Lastly, higher concentrations of MDE were correlated with a higher bacterial diversity throughout the investigation. The suitability of MDE as a nutrient supplement for the production of Tetraselmis sp. biomass and lipid is feasible. PMID:24971948

Erkelens, Mason; Ward, Andrew J; Ball, Andrew S; Lewis, David M

2014-09-01

328

Climate Change Impacts on Forest Succession and Future Productivity  

NASA Astrophysics Data System (ADS)

Change in ecosystem carbon (C) dynamics with forest succession is a long-studied topic in ecology, and secondary forests currently comprise a significant proportion of the global land base. Although mature forests are generally more important for conserving species and habitats, early successional trees and stands typically have higher rates of productivity, including net ecosystem productivity (NEP), which represents carbon available for sequestration. Secondary forests undergoing successional development are thus major players in the current global carbon cycle, yet how forests will function in the future under warmer conditions with higher atmospheric carbon dioxide (CO2) concentrations is unknown. Future forest C dynamics will depend, in part, on future species composition. Data from "Forests of the Future" research in a number of global change experiments provide insights into how forests may look in terms of dominant species composition, and thus function, in a future world. Studies at Free-Air Carbon Dioxide (FACE) experiments at Duke Forest and other facilities, plus climate warming experiments such as those at the Harvard Forest, suggest a common underlying principle of vegetation responses to environmental manipulation: Namely, that shade-tolerant woody species associating with arbuscular mycorrhizal (AM) fungi show greater growth stimulation than ectomycorrhizal-associating (ECM) trees which are more common in temperate and boreal forests (Fig. 1 of relative growth rates standardized by pre-treatment rates). This may be due in part to the role of AM fungi in obtaining soil phosphorus and inorganic forms of nitrogen for plant associates. In combination, these results suggest a shift in future forest composition towards less-productive tree species that generally acquire atmospheric CO2 at lower annual rates, as well as a competitive advantage extended to woody vines such as poison ivy. Due to higher atmospheric CO2 and warmer temperatures, forests of the future may become less-productive than those of today.

Mohan, J. E.; Melillo, J. M.; Clark, J. S.; Schlesinger, W. H.

2012-12-01

329

Anaerobic gut fungi: Advances in isolation, culture, and cellulolytic enzyme discovery for biofuel production.  

PubMed

Anaerobic gut fungi are an early branching family of fungi that are commonly found in the digestive tract of ruminants and monogastric herbivores. It is becoming increasingly clear that they are the primary colonizers of ingested plant biomass, and that they significantly contribute to the decomposition of plant biomass into fermentable sugars. As such, anaerobic fungi harbor a rich reservoir of undiscovered cellulolytic enzymes and enzyme complexes that can potentially transform the conversion of lignocellulose into bioenergy products. Despite their unique evolutionary history and cellulolytic activity, few species have been isolated and studied in great detail. As a result, their life cycle, cellular physiology, genetics, and cellulolytic metabolism remain poorly understood compared to aerobic fungi. To help address this limitation, this review briefly summarizes the current body of knowledge pertaining to anaerobic fungal biology, and describes progress made in the isolation, cultivation, molecular characterization, and long-term preservation of these microbes. We also discuss recent cellulase- and cellulosome-discovery efforts from gut fungi, and how these interesting, non-model microbes could be further adapted for biotechnology applications. Biotechnol. Bioeng. 2014;111: 1471-1482. © 2014 Wiley Periodicals, Inc. PMID:24788404

Haitjema, Charles H; Solomon, Kevin V; Henske, John K; Theodorou, Michael K; O'Malley, Michelle A

2014-08-01

330

Two stages catalytic pyrolysis of refuse derived fuel: production of biofuel via syncrude.  

PubMed

Thermo-catalytic pyrolysis of refuse derived fuels with different catalysts had been conducted in a two stages process due to its important potential value as fuel. The first stage was a pure thermal pyrolysis in a horizontal tubular reactor with feed rate of 0.5kg hourly. The second stage was a semi-batch process in the presence of catalysts. Results showed that the tested catalysts significantly have affected the quantity of products. E.g. gas yield could be increased with 350% related to the catalyst free case using ZSM-5, while that of pyrolytic oil was 115% over Y-zeolite. Gases consisted of mainly CO and CO(2) obtained from the tubular reactor, while dominantly hydrocarbons from the second stage. Ni-Mo-catalyst and Co-Mo-catalyst had shown activity in pyrolytic oil upgrading via in-situ hydrogenation-dehydrogenation reactions. Sulphur, nitrogen and chlorine level in pyrolytic oils could be significantly declined by using of catalysts. PMID:20663664

Miskolczi, N; Buyong, F; Angyal, A; Williams, P T; Bartha, L

2010-11-01

331

Immobilized anaerobic fermentation for bio-fuel production by Clostridium co-culture.  

PubMed

Clostridium thermocellum/Clostridium thermolacticum co-culture fermentation has been shown to be a promising way of producing ethanol from several carbohydrates. In this research, immobilization techniques using sodium alginate and alkali pretreatment were successfully applied on this co-culture to improve the bio-ethanol fermentation performance during consolidated bio-processing (CBP). The ethanol yield obtained increased by over 60 % (as a percentage of the theoretical maximum) as compared to free cell fermentation. For cellobiose under optimized conditions, the ethanol yields were approaching about 85 % of the theoretical efficiency. To examine the feasibility of this immobilization co-culture on lignocellulosic biomass conversion, untreated and pretreated aspen biomasses were also used for fermentation experiments. The immobilized co-culture shows clear benefits in bio-ethanol production in the CBP process using pretreated aspen. With a 3-h, 9 % NaOH pretreatment, the aspen powder fermentation yields approached 78 % of the maximum theoretical efficiency, which is almost twice the yield of the untreated aspen fermentation. PMID:24488259

Xu, Lei; Tschirner, Ulrike

2014-08-01

332

The path to next generation biofuels: successes and challenges in the era of synthetic biology.  

PubMed

Volatility of oil prices along with major concerns about climate change, oil supply security and depleting reserves have sparked renewed interest in the production of fuels from renewable resources. Recent advances in synthetic biology provide new tools for metabolic engineers to direct their strategies and construct optimal biocatalysts for the sustainable production of biofuels. Metabolic engineering and synthetic biology efforts entailing the engineering of native and de novo pathways for conversion of biomass constituents to short-chain alcohols and advanced biofuels are herewith reviewed. In the foreseeable future, formal integration of functional genomics and systems biology with synthetic biology and metabolic engineering will undoubtedly support the discovery, characterization, and engineering of new metabolic routes and more efficient microbial systems for the production of biofuels. PMID:20089184

Dellomonaco, Clementina; Fava, Fabio; Gonzalez, Ramon

2010-01-01

333

The path to next generation biofuels: successes and challenges in the era of synthetic biology  

PubMed Central

Volatility of oil prices along with major concerns about climate change, oil supply security and depleting reserves have sparked renewed interest in the production of fuels from renewable resources. Recent advances in synthetic biology provide new tools for metabolic engineers to direct their strategies and construct optimal biocatalysts for the sustainable production of biofuels. Metabolic engineering and synthetic biology efforts entailing the engineering of native and de novo pathways for conversion of biomass constituents to short-chain alcohols and advanced biofuels are herewith reviewed. In the foreseeable future, formal integration of functional genomics and systems biology with synthetic biology and metabolic engineering will undoubtedly support the discovery, characterization, and engineering of new metabolic routes and more efficient microbial systems for the production of biofuels.

2010-01-01

334

World crop residues production and implications of its use as a biofuel.  

PubMed

Reducing and off-setting anthropogenic emissions of CO(2) and other greenhouse gases (GHGs) are important strategies of mitigating the greenhouse effect. Thus, the need for developing carbon (C) neutral and renewable sources of energy is more than ever before. Use of crop residue as a possible source of feedstock for bioenergy production must be critically and objectively assessed because of its positive impact on soil C sequestration, soil quality maintenance and ecosystem functions. The amount of crop residue produced in the US is estimated at 367x10(6) Mg/year for 9 cereal crops, 450x10(6) Mg/year for 14 cereals and legumes, and 488x10(6) Mg/year for 21 crops. The amount of crop residue produced in the world is estimated at 2802x10(6) Mg/year for cereal crops, 3107x10(6) Mg/year for 17 cereals and legumes, and 3758x10(6) Mg/year for 27 food crops. The fuel value of the total annual residue produced is estimated at 1.5x10(15) kcal, about 1 billion barrels (bbl) of diesel equivalent, or about 8 quads for the US; and 11.3x10(15) kcal, about 7.5 billion bbl of diesel or 60 quads for the world. However, even a partial removal (30-40%) of crop residue from land can exacerbate soil erosion hazard, deplete the SOC pool, accentuate emission of CO(2) and other GHGs from soil to the atmosphere, and exacerbate the risks of global climate change. Therefore, establishing bioenergy plantations of site-specific species with potential of producing 10-15 Mg biomass/year is an option that needs to be considered. This option will require 40-60 million hectares of land in the US and about 250 million hectares worldwide to establish bioenergy plantations. PMID:15788197

Lal, R

2005-05-01

335

Biofuels coproducts tolerance and toxicology for ruminants.  

PubMed

The rapid growth of the biofuels industry in the Midwest in the past 10 years has created an increased supply of corn coproduct feed for animals. This article discusses the tolerance and toxicology of biofuels coproducts in ruminants, including polioencephalomalacia, sulfur toxicosis, sulfur metabolism, mycotoxins, antibiotic residue, and biodiesel by-product toxicosis. PMID:21575771

Ensley, Steve

2011-07-01

336

Stakeholder perceptions of biofuels from microalgae  

Microsoft Academic Search

In this paper we focus on stakeholder views around the development of advanced biofuels from microalgae. Research for the development of microalgal-derived biofuels was initiated by the US Department of Energy (DOE) more than 30 years ago. However, interest in this eco-innovation has been growing significantly over the last five years in various countries. The high productivity of algae indicates

Christian Oltra

2011-01-01

337

Prediction of the future number of wells in production  

SciTech Connect

A method to predict the number of wells that will continue producing at a certain date in the future is presented. The method is applicable to reservoirs of the depletion type and is based on the survival probability concept. This is useful when forecasting by empirical methods. An example of a field in primary production is presented.

Coca, B.P.

1981-01-01

338

Mass spectrometry of natural products: current, emerging and future technologies.  

PubMed

Although mass spectrometry is a century old technology, we are entering into an exciting time for the analysis of molecular information directly from complex biological systems. In this Highlight, we feature emerging mass spectrometric methods and tools used by the natural product community and give a perspective of future directions where the mass spectrometry field is migrating towards over the next decade. PMID:24801551

Bouslimani, Amina; Sanchez, Laura M; Garg, Neha; Dorrestein, Pieter C

2014-06-14

339

Water requirements for future energy production in California  

Microsoft Academic Search

This assessment estimates the impact of future national energy development on water resources. Energy development would include various types of electric power plants, production of synthetic fuels, coal and uranium mining, oil and gas extraction, and other conversion processes. The Energy Analysis Program at LBL has conducted this analysis for its assigned region, the states of California and Nevada. The

J. A. Sathaye; R. L. Ritschard

1977-01-01

340

Synergies between bio- and oil refineries for the production of fuels from biomass.  

PubMed

As petroleum prices continue to increase, it is likely that biofuels will play an ever-increasing role in our energy future. The processing of biomass-derived feedstocks (including cellulosic, starch- and sugar-derived biomass, and vegetable fats) by catalytic cracking and hydrotreating is a promising alternative for the future to produce biofuels, and the existing infrastructure of petroleum refineries is well-suited for the production of biofuels, allowing us to rapidly transition to a more sustainable economy without large capital investments for new reaction equipment. This Review discusses the chemistry, catalysts, and challenges involved in the production of biofuels. PMID:17610226

Huber, George W; Corma, Avelino

2007-01-01

341

Biofuels and the conundrum of sustainability.  

PubMed

Sustainable energy is the problem of the 21st century. If biofuels want to be part of the solution they must accept a degree of scrutiny unprecedented in the development of a new industry. That is because sustainability deals explicitly with the role of biofuels in ensuring the well-being of our planet, our economy, and our society both today and in the future. Life cycle assessment (LCA) has been the standard framework for assessing sustainability of biofuels. These assessments show that corn ethanol has a marginally lower fossil energy and greenhouse gas footprint compared to petroleum fuel. Sugarcane ethanol and some forms of biodiesel offer substantially lower footprints. New biofuels may offer low footprints. The science of LCA is being stretched to its limits as policy makers consider direct and indirect effects of biofuels on global land and water resources, global ecosystems, air quality, public health, and social justice. PMID:19553101

Sheehan, John J

2009-06-01

342

Biofuels from Microalgae and Seaweeds  

SciTech Connect

8.1 Introduction: Seaweeds and microalgae have a long history of cultivation as sources of commercial products (McHugh 2003; Pulz and Gross 2004). They also have been the subject of extensive investigations related to their potential as fuel source since the 1970s (Chynoweth 2002). As energy costs rise, these photosynthetic organisms are again a focus of interest as potential sources of biofuels, particularly liquid transportation fuels. There have been many recent private sector investments to develop biofuels from microalgae, in part building on a U.S. Department of Energy (DOE) program from 1976 to 1996 which focused on microalgal oil production (Sheehan et al. 1998). Seaweed cultivation has received relatively little attention as a biofuel source in the US, but was the subject of a major research effort by the DOE from 1978 to 1983 (Bird and Benson 1987), and is now the focus of significant interest in Japan, Europe and Korea...

Huesemann, Michael H.; Roesijadi, Guritno; Benemann, John; Metting, F. Blaine

2010-03-01

343

Development of Cellulosic Biofuels  

ScienceCinema

Chris Somerville, Director of the Energy Biosciences Institute and an award-winning plant biochemist with Berkeley Lab's Physical Biosciences Division, is a leading authority on the structure and function of plant cell walls. He discusses an overview of some of the technical challenges associated with the production of cellulosic biofuels, which will require an improved understanding of a diverse range of topics in fields such as agronomy, chemical engineering, microbiology, structural biology, genomics, environmental sciences, and socioeconomics. His talk was presented June 20, 2007.

Chris Somerville

2013-06-17

344

Development of Cellulosic Biofuels  

ScienceCinema

Chris Somerville, Director of the Energy Biosciences Institute and an award-winning plant biochemist with Berkeley Lab's Physical Biosciences Division, is a leading authority on the structure and function of plant cell walls. He discusses an overview of some of the technical challenges associated with the production of cellulosic biofuels, which will require an improved understanding of a diverse range of topics in fields such as agronomy, chemical engineering, microbiology, structural biology, genomics, environmental sciences, and socioeconomics. His talk was presented June 20, 2007.

LBNL

2009-09-01

345

Development of Cellulosic Biofuels  

ScienceCinema

Chris Somerville, Director of the Energy Biosciences Institute and an award-winning plant biochemist with Berkeley Lab's Physical Biosciences Division, is a leading authority on the structure and function of plant cell walls. He discusses an overview of some of the technical challenges associated with the production of cellulosic biofuels, which will require an improved understanding of a diverse range of topics in fields such as agronomy, chemical engineering, microbiology, structural biology, genomics, environmental sciences, and socioeconomics. His talk was presented June 20, 2007.

Chris Somerville

2010-01-08

346

CONNECTICUT BIOFUELS TECHNOLOGY PROJECT  

SciTech Connect

DBS Energy Inc. (“DBS”) intends on using the Connecticut Biofuels Technology Project for the purpose of developing a small-scale electric generating systems that are located on a distributed basis and utilize biodiesel as its principle fuel source. This project will include research and analysis on the quality and applied use of biodiesel for use in electricity production, 2) develop dispatch center for testing and analysis of the reliability of dispatching remote generators operating on a blend of biodiesel and traditional fossil fuels, and 3) analysis and engineering research on fuel storage options for biodiesel of fuels for electric generation.

BARTONE, ERIK

2010-09-28

347

Development of Cellulosic Biofuels  

SciTech Connect

Chris Somerville, Director of the Energy Biosciences Institute and an award-winning plant biochemist with Berkeley Lab's Physical Biosciences Division, is a leading authority on the structure and function of plant cell walls. He discusses an overview of some of the technical challenges associated with the production of cellulosic biofuels, which will require an improved understanding of a diverse range of topics in fields such as agronomy, chemical engineering, microbiology, structural biology, genomics, environmental sciences, and socioeconomics. His talk was presented June 20, 2007.

Chris Somerville

2008-03-12

348

Microbial production of a biofuel (acetone-butanol-ethanol) in a continuous bioreactor: impact of bleed and simultaneous product removal.  

PubMed

Acetone butanol ethanol (ABE) was produced in an integrated continuous one-stage fermentation and gas stripping product recovery system using Clostridium beijerinckii BA101 and fermentation gases (CO(2) and H(2)). In this system, the bioreactor was fed with a concentrated sugar solution (250-500 g L(-1) glucose). The bioreactor was bled semi-continuously to avoid accumulation of inhibitory chemicals and products. The continuous system was operated for 504 h (21 days) after which the fermentation was intentionally terminated. The bioreactor produced 461.3 g ABE from 1,125.0 g total sugar in 1 L culture volume as compared to a control batch process in which 18.4 g ABE was produced from 47.3 g sugar. These results demonstrate that ABE fermentation can be operated in an integrated continuous one-stage fermentation and product recovery system for a long period of time, if butanol and other microbial metabolites in the bioreactor are kept below threshold of toxicity. PMID:22729675

Ezeji, Thaddeus Chukwuemeka; Qureshi, Nasib; Blaschek, Hans Peter

2013-01-01

349

Heterotrophic growth and lipid accumulation of Chlorella protothecoides in whey permeate, a dairy by-product stream, for biofuel production.  

PubMed

This study proposes a novel alternative for the utilization of whey permeate, a by-product stream from the dairy industry, as the feedstock for the biomass and lipid production of the microalgae Chlorella protothecoides. Glucose and galactose from the pre-hydrolyzed whey permeate were used as main carbon sources in a base mineral media for establishing batch and fed batch cultures. Batch cultures reached a biomass production of 9.1±0.2g/L with a total lipid accumulation of 42.0±6.6% (dry weight basis), while in the fed batch cultures 17.2±1.3g/L of biomass with 20.5±0.3% lipid accumulation (dry weight basis) were obtained. A third strategy for the direct utilization of whey permeate was investigated by simultaneous saccharification and fermentation (SSF), wherein, 7.3±1.3g/L of biomass with 49.9±3.3% lipid accumulation (dry weight basis) was obtained in batch mode using immobilized enzyme. PMID:24445193

Espinosa-Gonzalez, Isabel; Parashar, Archana; Bressler, David C

2014-03-01

350

Teapot dome: past, present, and future. [Oil field productivity  

Microsoft Academic Search

The Teapot Dome field is the 99th largest oil field in the U.S. with a proved reserve of 42,515,000 bbl, yet the field is sparsely drilled and underdeveloped. Naval Petroleum Reserve No. 3 is credited with 38 million bbl of future reserves. Oil production in the Teapot Dome field is from 3 formations--the shallow Shannon at depths of 400 to

W. H. Jr

1977-01-01

351

Biofuels, Greenhouse Gases and Climate Change  

Microsoft Academic Search

\\u000a Biofuels are fuels produced from biomass, mostly in liquid form, within a time frame sufficiently short to consider that their\\u000a feedstock (biomass) can be renewed, contrarily to fossil fuels. This paper reviews the current and future biofuel technologies,\\u000a and their development impacts (including on the climate) within given policy and economic frameworks. Current technologies\\u000a make it possible to provide first

Cécile Bessou; Fabien Ferchaud; Benoît Gabrielle; Bruno Mary

352

Biotechnological production of muconic acid: current status and future prospects.  

PubMed

Muconic acid (MA), a high value-added bio-product with reactive dicarboxylic groups and conjugated double bonds, has garnered increasing interest owing to its potential applications in the manufacture of new functional resins, bio-plastics, food additives, agrochemicals, and pharmaceuticals. At the very least, MA can be used to produce commercially important bulk chemicals such as adipic acid, terephthalic acid and trimellitic acid. Recently, great progress has been made in the development of biotechnological routes for MA production. This present review provides a comprehensive and systematic overview of recent advances and challenges in biotechnological production of MA. Various biological methods are summarized and compared, and their constraints and possible solutions are also described. Finally, the future prospects are discussed with respect to the current state, challenges, and trends in this field, and the guidelines to develop high-performance microbial cell factories are also proposed for the MA production by systems metabolic engineering. PMID:24751381

Xie, Neng-Zhong; Liang, Hong; Huang, Ri-Bo; Xu, Ping

2014-01-01

353

Engineering biofuel tolerance in non-native producing microorganisms.  

PubMed

Large-scale production of renewable biofuels through microbiological processes has drawn significant attention in recent years, mostly due to the increasing concerns on the petroleum fuel shortages and the environmental consequences of the over-utilization of petroleum-based fuels. In addition to native biofuel-producing microbes that have been employed for biofuel production for decades, recent advances in metabolic engineering and synthetic biology have made it possible to produce biofuels in several non-native biofuel-producing microorganisms. Compared to native producers, these non-native systems carry the advantages of fast growth, simple nutrient requirements, readiness for genetic modifications, and even the capability to assimilate CO2 and solar energy, making them competitive alternative systems to further decrease the biofuel production cost. However, the tolerance of these non-native microorganisms to toxic biofuels is naturally low, which has restricted the potentials of their application for high-efficiency biofuel production. To address the issues, researches have been recently conducted to explore the biofuel tolerance mechanisms and to construct robust high-tolerance strains for non-native biofuel-producing microorganisms. In this review, we critically summarize the recent progress in this area, focusing on three popular non-native biofuel-producing systems, i.e. Escherichia coli, Lactobacillus and photosynthetic cyanobacteria. PMID:24530635

Jin, Hu; Chen, Lei; Wang, Jiangxin; Zhang, Weiwen

2014-01-01

354

World Biofuels Study.  

National Technical Information Service (NTIS)

This report forms part of a project entitled 'World Biofuels Study'. The objective is to study world biofuel markets and to examine the possible contribution that biofuel imports could make to help meet the Renewable Fuel Standard (RFS) of the Energy Inde...

T. Alfstad

2008-01-01

355

Indirect land use changes of biofuel production - a review of modelling efforts and policy developments in the European Union  

PubMed Central

The issue of indirect land use changes (ILUC) caused by the promotion of transport biofuels has attracted considerable attention in recent years. In this paper, we reviewed the current literature on modelling work to estimate emissions of greenhouse gases (GHG) caused by ILUC of biofuels. We also reviewed the development of ILUC policies in the EU. Our review of past modelling work revealed that most studies employ economic equilibrium modelling and focus on ethanol fuels, especially with maize as feedstock. It also revealed major variation in the results from the models, especially for biodiesel fuels. However, there has been some convergence of results over time, particularly for ethanol from maize, wheat and sugar cane. Our review of EU policy developments showed that the introduction of fuel-specific ILUC factors has been officially suggested by policymakers to deal with the ILUC of biofuels. The values proposed as ILUC factors in the policymaking process in the case of ethanol fuels are generally in line with the results of the latest modelling exercises, in particular for first-generation ethanol fuels from maize and sugar cane, while those for biodiesel fuels are somewhat higher. If the proposed values were introduced into EU policy, no (first-generation) biodiesel fuel would be able to comply with the EU GHG saving requirements. We identified a conflict between the demand from EU policymakers for exact, highly specific values and the capacity of the current models to supply results with that level of precision. We concluded that alternative policy approaches to ILUC factors should be further explored.

2014-01-01

356

The Biofuel Feedstock Genomics Resource: a web-based portal and database to enable functional genomics of plant biofuel feedstock species  

PubMed Central

Major feedstock sources for future biofuel production are likely to be high biomass producing plant species such as poplar, pine, switchgrass, sorghum and maize. One active area of research in these species is genome-enabled improvement of lignocellulosic biofuel feedstock quality and yield. To facilitate genomic-based investigations in these species, we developed the Biofuel Feedstock Genomic Resource (BFGR), a database and web-portal that provides high-quality, uniform and integrated functional annotation of gene and transcript assembly sequences from species of interest to lignocellulosic biofuel feedstock researchers. The BFGR includes sequence data from 54 species and permits researchers to view, analyze and obtain annotation at the gene, transcript, protein and genome level. Annotation of biochemical pathways permits the identification of key genes and transcripts central to the improvement of lignocellulosic properties in these species. The integrated nature of the BFGR in terms of annotation methods, orthologous/paralogous relationships and linkage to seven species with complete genome sequences allows comparative analyses for biofuel feedstock species with limited sequence resources. Database URL: http://bfgr.plantbiology.msu.edu

Childs, Kevin L.; Konganti, Kranti; Buell, C. Robin

2012-01-01

357

Forces Shaping Future U.S. Coal Production and Use  

USGS Publications Warehouse

More than half of the electricity in the United States is generated by coal-fired powerplants. U.S. coal producers sell almost 90 percent of their product for electricity generation, and so, the future of the U.S. coal industry will be determined by the future of coal-fired electricity-generation plants. The U.S. Geological Survey (USGS) is completing a National Coal Resource Assessment (NCRA) of five major coal-producing regions of the United States (fig. 1): (1) the Appalachian Basin, (2) the Illinois Basin, (3) the Gulf Coast, (4) the Colorado Plateau, and (5) the Northern Rocky Mountains and Great Plains. The Powder River and Williston Basins are the principal producing areas of the Northern Rocky Mountains and Great Plains region.

Attanasi, Emil D.; Pierce, Brenda S.

2001-01-01

358

Biofuel cells--recent advances and applications.  

PubMed

In 2006, the journal Biosensors and Bioelectronics published a special issue devoted exclusively to biofuel cells, including several research papers and an extensive review of the field [Bullen, R.A., Arnot, T.C., Lakeman, J.B., Walsh, F.C., 2006. Biosens. Bioelectron.]. Within this review a brief description will firstly be given of the history of biofuel cells together with coverage of some of the major historical advances. The review is intended, however, to largely concentrate on and give an overview of the advances made in recent years in this area together with a discussion surrounding the practical application of biofuel cells. There are several classes of biofuel cells: we shall firstly discuss the recent advances in biofuel cells that convert chemical fuels to produce electrical power by use of catalytic enzymes. This will be followed by a section on similar cells where micro-organisms rather than enzymes are used to convert the fuel to energy. Thirdly we shall consider hybrid biofuel cells that combine the utilisation of photochemical chemistries and biological systems for the generation of electricity. Finally we will discuss some of the proposed uses of biofuel cells together with a short consideration of future research possibilities and applications of these systems. PMID:16781864

Davis, Frank; Higson, Séamus P J

2007-02-15

359

Computational Resources for Biofuel Feedstock Species. Final Progress Report August 15, 2008 to August 14, 2012.  

National Technical Information Service (NTIS)

While current production of ethanol as a biofuel relies on starch and sugar inputs, it is anticipated that sustainable production of ethanol for biofuel use will utilize lignocellulosic feedstocks. Candidate plant species to be used for lignocellulosic et...

2012-01-01

360

Biofuels from algae: challenges and potential  

PubMed Central

Algae biofuels may provide a viable alternative to fossil fuels; however, this technology must overcome a number of hurdles before it can compete in the fuel market and be broadly deployed. These challenges include strain identification and improvement, both in terms of oil productivity and crop protection, nutrient and resource allocation and use, and the production of co-products to improve the economics of the entire system. Although there is much excitement about the potential of algae biofuels, much work is still required in the field. In this article, we attempt to elucidate the major challenges to economic algal biofuels at scale, and improve the focus of the scientific community to address these challenges and move algal biofuels from promise to reality.

Hannon, Michael; Gimpel, Javier; Tran, Miller; Rasala, Beth; Mayfield, Stephen

2011-01-01

361

Biofuels from algae: challenges and potential.  

PubMed

Algae biofuels may provide a viable alternative to fossil fuels; however, this technology must overcome a number of hurdles before it can compete in the fuel market and be broadly deployed. These challenges include strain identification and improvement, both in terms of oil productivity and crop protection, nutrient and resource allocation and use, and the production of co-products to improve the economics of the entire system. Although there is much excitement about the potential of algae biofuels, much work is still required in the field. In this article, we attempt to elucidate the major challenges to economic algal biofuels at scale, and improve the focus of the scientific community to address these challenges and move algal biofuels from promise to reality. PMID:21833344

Hannon, Michael; Gimpel, Javier; Tran, Miller; Rasala, Beth; Mayfield, Stephen

2010-09-01

362

The DSCOVR Solar Wind Mission and Future Space Weather Products  

NASA Astrophysics Data System (ADS)

The Deep Space Climate Observatory (DSCOVR) mission, scheduled for launch in mid-2014, will provide real-time solar wind thermal plasma and magnetic measurements to ensure continuous monitoring for space weather forecasting. DSCOVR will orbit L1 and will serve as a follow-on mission to NASA's Advanced Composition Explorer (ACE), which was launched in 1997. DSCOVR will have a total of six instruments, two of which will provide real-time data necessary for space weather forecasting: a Faraday cup to measure the proton and alpha components of the solar wind, and a triaxial fluxgate magnetometer to measure the magnetic field in three dimensions. Real-time data provided by DSCOVR will include Vx, Vy, Vz, n, T, Bx, By, and Bz. Such real-time L1 data is used in generating space weather applications and products that have been demonstrated to be highly accurate and provide actionable information for customers. We evaluate current space weather products driven by ACE and discuss future products under development for DSCOVR. New space weather products under consideration include: automated shock detection, more accurate L1 to Earth delay time, and prediction of rotations in solar wind Bz within magnetic clouds. Suggestions from the community on product ideas are welcome.

Cash, M. D.; Biesecker, D. A.; Reinard, A. A.

2012-12-01

363

Engineering microbes for tolerance to next-generation biofuels  

PubMed Central

A major challenge when using microorganisms to produce bulk chemicals such as biofuels is that the production targets are often toxic to cells. Many biofuels are known to reduce cell viability through damage to the cell membrane and interference with essential physiological processes. Therefore, cells must trade off biofuel production and survival, reducing potential yields. Recently, there have been several efforts towards engineering strains for biofuel tolerance. Promising methods include engineering biofuel export systems, heat shock proteins, membrane modifications, more general stress responses, and approaches that integrate multiple tolerance strategies. In addition, in situ recovery methods and media supplements can help to ease the burden of end-product toxicity and may be used in combination with genetic approaches. Recent advances in systems and synthetic biology provide a framework for tolerance engineering. This review highlights recent targeted approaches towards improving microbial tolerance to next-generation biofuels with a particular emphasis on strategies that will improve production.

2011-01-01

364

Engineering microbes for tolerance to next-generation biofuels.  

PubMed

A major challenge when using microorganisms to produce bulk chemicals such as biofuels is that the production targets are often toxic to cells. Many biofuels are known to reduce cell viability through damage to the cell membrane and interference with essential physiological processes. Therefore, cells must trade off biofuel production and survival, reducing potential yields. Recently, there have been several efforts towards engineering strains for biofuel tolerance. Promising methods include engineering biofuel export systems, heat shock proteins, membrane modifications, more general stress responses, and approaches that integrate multiple tolerance strategies. In addition, in situ recovery methods and media supplements can help to ease the burden of end-product toxicity and may be used in combination with genetic approaches. Recent advances in systems and synthetic biology provide a framework for tolerance engineering. This review highlights recent targeted approaches towards improving microbial tolerance to next-generation biofuels with a particular emphasis on strategies that will improve production. PMID:21936941

Dunlop, Mary J

2011-01-01

365

Biofuel from biomass via photo-electrochemical reactions: An overview  

NASA Astrophysics Data System (ADS)

Biomass is attracting a great deal of attention as a renewable energy resource to reduce carbon dioxide (CO2) emissions. Converting biomass from municipal, agricultural and livestock into biofuel and electrical power has significant environmental and economic advantages. The conversion of biomass into practical energy requires elegant designs and further investigation. Thus, biomass is a promising renewable energy source due to its low production cost and simple manufacturing processes. Biofuel (hydrogen and methanol) from biomass will be possible to be used for transportation with near-zero air pollution, involves efficient uses of land and major contribution to reduce dependence on insecure source of petroleum. Photoelectrochemical (PEC) reactions study has potential pathway for producing fuel from biomass and bio-related compound in the near future. This review highlights recent work related to the PEC conversion of biomass and bio-related compounds into useful biofuels and electricity. This review covers different types of photochemical reaction cells utilizing various types of organic and inorganic waste. It also presents recent developments in photoelectrodes, photocatalysts and electrolytes as well as the production of different types of fuel from PEC cells and highlights current developments and problems in PEC reactions.

Ibrahim, N.; Kamarudin, S. K.; Minggu, L. J.

366

STATUS OF THE NOAA\\/NESDIS OPERATIONAL SATELLITE WIND PRODUCT SYSTEM: RECENT IMPROVEMENTS, NEW PRODUCTS, PRODUCT QUALITY, AND FUTURE PLANS  

Microsoft Academic Search

This paper provides a summary of the status of the NOAA\\/NESDIS operational satellite wind product system. Recent improvements, new additions, future plans and product quality assessment of the Atmospheric Motion Vector (AMV) product suite will be discussed. GOES-10 still serves as the western operational geostationary satellite and GOES-9 has been activated to provide coverage over the western Pacific for the

Jaime Daniels; Christopher Velden; Wayne Bresky; Antonio Irving

367

Future Opportunities in Production Agriculture-Energy from Farm Land Evaluation of Perennial Herbaceous Biomass Energy Crops in North Dakota  

Microsoft Academic Search

A biorefinery is a processing and conversion facility that efficiently separates biomass feedstock into individual components and converts these components into marketplace products, including biofuels, biopower, and bioproducts. Biorefinery technologies, such as biochemical conversion (fermentation), thermochemical conversion (gasification and fast pyrolysis), and hybrid thermochemical and biochemical technologies, are currently being developed and will be placed in commercial production by 2009

Ezra Aberle; D. K. Lee; Blaine Schatz; Paul Nyren

368

Next-generation biofuels: Survey of emerging technologies and sustainability issues.  

PubMed

Next-generation biofuels, such as cellulosic bioethanol, biomethane from waste, synthetic biofuels obtained via gasification of biomass, biohydrogen, and others, are currently at the center of the attention of technologists and policy makers in search of the more sustainable biofuel of tomorrow. To set realistic targets for future biofuel options, it is important to assess their sustainability according to technical, economical, and environmental measures. With this aim, the review presents a comprehensive overview of the chemistry basis and of the technology related aspects of next generation biofuel production, as well as it addresses related economic issues and environmental implications. Opportunities and limits are discussed in terms of technical applicability of existing and emerging technology options to bio-waste feedstock, and further development forecasts are made based on the existing social-economic and market situation, feedstock potentials, and other global aspects. As the latter ones are concerned, the emphasis is placed on the opportunities and challenges of developing countries in adoption of this new industry. PMID:20922754

Zinoviev, Sergey; Müller-Langer, Franziska; Das, Piyali; Bertero, Nicolás; Fornasiero, Paolo; Kaltschmitt, Martin; Centi, Gabriele; Miertus, Stanislav

2010-10-25

369

Biofuels and the need for additional carbon  

NASA Astrophysics Data System (ADS)

Use of biofuels does not reduce emissions from energy combustion but may offset emissions by increasing plant growth or by reducing plant residue or other non-energy emissions. To do so, biofuel production must generate and use 'additional carbon', which means carbon that plants would not otherwise absorb or that would be emitted to the atmosphere anyway. When biofuels cause no direct land use change, they use crops that would grow regardless of biofuels so they do not directly absorb additional carbon. All potential greenhouse gas reductions from such biofuels, as well as many potential emission increases, result from indirect effects, including reduced crop consumption, price-induced yield gains and land conversion. If lifecycle analyses ignore indirect effects of biofuels, they therefore cannot properly find greenhouse gas reductions. Uncertainties in estimating indirect emission reductions and increases are largely symmetrical. The failure to distinguish 'additional' carbon from carbon already absorbed or withheld from the atmosphere also leads to large overestimates of global bioenergy potential. Reasonable confidence in greenhouse gas reductions requires a precautionary approach to estimating indirect effects that does not rely on any single model. Reductions can be more directly assured, and other adverse indirect effects avoided, by focusing on biofuels from directly additional carbon.

Searchinger, Timothy D.

2010-04-01

370

Biofuel from "humified" biomass  

NASA Astrophysics Data System (ADS)

In France, 26% of the emissions of greenhouse effect gas originate from transportation which depends for 87% on fossil fuels. Nevertheless biofuels can contribute to the fight against climate change while reducing energetic dependence. Indeed biomass potentially represents in France 30 Mtoe a year that is to say 15% national consumption. But 80% of these resources are made of lignocellulosic materials which are hardly exploitable. First-generation biofuels are made from sugar, starch, vegetable oil, or animal fats. Due to their competition with human food chain, first-generation biofuels could lead to food shortages and price rises. At the contrary second-generation biofuel production can use a variety of non food crops while using the lignocellulosic part of biomass [1]. Gasification, fermentation and direct pyrolysis are the most used processes. However weak yields and high hydrogen need are limiting factors. In France, the National Program for Research on Biofuels (PNRB) aims to increase mobilizable biomass resource and to develop lignocellulosic biomass conversion. In this context, the LIGNOCARB project studies the liquefaction of biodegraded biomass in order to lower hydrogen consumption. Our aim was to develop and optimize the biodegradation of the biomass. Once the reactor was achieved, the influence of different parameters (starting material, aeration, moisture content) on the biotransformation process was studied. The monitored parameters were temperature, pH and carbon /nitrogen ratio. Chemical (IHSS protocol) and biochemical (van Soest) fractionations were used to follow the maturity ("humic acid"/"fulvic acid" ratio) and the biological stability (soluble, hemicelluloses, celluloses, lignin) of the organic matter (OM). In example, the increase in lignin can be related to the stabilization since the OM becomes refractory to biodegradation whereas the increase in the AH/AF ratio traduces "humification". However, contrarily to the composting process, we do not look forward to obtain a mature OM for which the carbon loss would be too important. The global analysis of the biomass OM during biodegradation using infrared spectroscopy (DRIFTS) confirms "humification". Indeed the relative intensity of bands associated to aromatics increase relatively to those associated to aliphatics[2] [3]. The molecular study of lipids and humic fractions was realised using mass spectrometry (GC/MS), pyrolysis (Py-GC/MS) and thermodesorption (Headspace-GC/MS). The decrease in lipids indicates a high biodegradation. Amongst volatile organic compounds (COVs), the isoprenoid C18 ketone which is probably produced from biodegradation of phytol is observed in all our samples. The organic matter obtained after biodegradation is stable (resistant to biodegradation) and humified but still rich in carbon. The characterisation of bacterial biomarkers will help us to specify and thus to optimize biotransformation mechanisms. [1] A. Dermirbas and Al, Progress in energy and combustion science, 33 (2007), 1 - 18. [2] P. Castaldi and Al, Waste Management, 25 (2005), 213 - 217. [3] Mr. Crube and Al, Geoderma, 130 2006, 1573 - 1586.

Kpogbemabou, D.; Lemée, L.; Amblès, A.

2009-04-01

371

Biofuels in China  

NASA Astrophysics Data System (ADS)

The Chinese government is stimulating the biofuels development to replace partially fossil fuels in the transport sector, which can enhance energy security, reduce greenhouse gas emissions, and stimulate rural development. Bioethanol, biodiesel, biobutanol, biogas, and biohydrogen are the main biofuels developed in China. In this chapter, we mainly present the current status of biofuel development in China, and illustrate the issues of feedstocks, food security and conversion processes.

Tan, Tianwei; Yu, Jianliang; Lu, Jike; Zhang, Tao

372

Environmental performance of algal biofuel technology options.  

PubMed

Considerable research and development is underway to produce fuels from microalgae, one of several options being explored for increasing transportation fuel supplies and mitigating greenhouse gas emissions (GHG). This work models life-cycle GHG and on-site freshwater consumption for algal biofuels over a wide technology space, spanning both near- and long-term options. The environmental performance of algal biofuel production can vary considerably and is influenced by engineering, biological, siting, and land-use considerations. We have examined these considerations for open pond systems, to identify variables that have a strong influence on GHG and freshwater consumption. We conclude that algal biofuels can yield GHG reductions relative to fossil and other biobased fuels with the use of appropriate technology options. Further, freshwater consumption for algal biofuels produced using saline pond systems can be comparable to that of petroleum-derived fuels. PMID:22324757

Vasudevan, Venkatesh; Stratton, Russell W; Pearlson, Matthew N; Jersey, Gilbert R; Beyene, Abraham G; Weissman, Joseph C; Rubino, Michele; Hileman, James I

2012-02-21

373

Future electricity production methods. Part 1: Nuclear energy  

NASA Astrophysics Data System (ADS)

The global warming challenge aims at stabilizing the concentrations of Green House Gas (GHG) in the atmosphere. Carbon dioxide is the most effective of the anthropogenic GHG and is essentially produced by consumption of fossil fuels. Electricity production is the dominant cause of CO2 emissions. It is, therefore, crucial that the share of 'carbon less' electricity production techniques increases at a fast pace. This is the more so, that 'clean' electricity would be useful to displace 'dirty' techniques in other fields such as heat production and transportation. Here we examine the extent to which nuclear energy could be operational in providing 'clean' electricity. A nuclear intensive scenario is shown to give the possibility to divide CO2 emissions by a factor of 2 worldwide, within 50 years. However, the corresponding sharp increase in nuclear power will put a heavy burden on uranium reserves and will necessitate the development of breeding reactors as soon as possible. A review of present and future reactors is given with special attention to the safety issues. The delicate question of nuclear fuel cycle is discussed concerning uranium reserves and management of used fuels. It is shown that dealing with nuclear wastes is more a socio-political problem than a technical one. The third difficult question associated with the development of nuclear energy is the proliferation risk. It is advocated that, while this is, indeed, a very important question, it is only weakly related to nuclear power development. Finally, the possibilities of nuclear fusion are discussed and it is asserted that, under no circumstances, could nuclear fusion give a significant contribution to the solution of the energy problem before 50 years, too late for dealing with the global warming challenge.

Nifenecker, Hervé

2011-02-01

374

Water quality within biofuel production landscape: Integrating flow paths, residence time distribution and mixing dynamics in the stream side management zone  

NASA Astrophysics Data System (ADS)

Best Management Practices designed to protect water quality are largely based on empirical studies of runoff from various cropping practices and associated mitigation strategies. Application of the resulting mitigation strategies has resulted in significant improvements in water quality, particularly reductions in sediment yields. Watershed modeling can extend the observations to other crops, landscapes and climates, but extrapolation is often compromised by too many model parameters and assumptions. The sheer number of potential dedicated biofuel-biochemical crop species, crop practices and hydrologic landscapes makes it difficult to comprehensively test various alternatives when the final configurations are largely unknown. We argue that a dominant hydrologic process framework for evaluating and mitigating potential water quality impacts can be constructed from basic hydrologic principles coupled to the crop fertilizer uptake efficiency and pesticide properties. We illustrate the approach in the southeastern U.S. on an old-field landscape with zero and first order streams suitable for cellulosic biofuel crops. In this region nitrogen additions are essential to sustain and enhance production and herbicides are frequently required for establishment. If overland flow is effectively managed, the primary flow path transmits water to groundwater and contaminates are subject to dispersion, sorption, and biochemical reaction. Average residence times in headwater basins typically ranges from3-12 years. However, the array of flow paths and distribution of residence times may lead to undesirable transport of contaminates. For example, significant lateral interflow may occur within 25-50 meters of the stream interface. Transmissions of these materials through the biological active riparian zones can substantially reduce contaminate concentrations as long as flux rates do not exceed uptake rates. To the extent that subsurface interflow and groundwater dynamics can be characterized by topographic configurations, these areas can be managed with more conservative practices or crops without seriously hindering production. In this study, we are monitoring hydrological and chemical state variables and fluxes throughout headwater watersheds to test modeling ideas for extrapolating these observations to various woody bioenergy crop production systems. Our working hypothesis is that hydrologic principles can enable us to bridge the knowledge gaps between empirical trials and modeling to support sustainable practices until commercial operations are implemented.

Blake, J. I.; Jackson, C. R.; Griffiths, N. A.; Klaus, J.; Du, E.; Vache, K. B.; McDonnell, J. J.

2012-12-01

375

The spatial and temporal shifts of biofuel production in the ecosystem-level carbon and water dynamics in the central plains of US  

NASA Astrophysics Data System (ADS)

The grasslands of the central plains US are the leading producer of wheat, sorghum and a significant amount of corn and soybean. By linking the food production and energy cycles, increasing demand for ethanol, biodiesel, and food, not only regional ecosystems are altered by the influences of Land-Use Land-Cover (LULC), but it is also a challenge for us to gain more knowledge about the carbon balance on fuel and food. In order to ascertain the impacts of changing LULC on carbon and water dynamics, more specifically, to examine the impacts of altering current land cover to increase biofuel production in this region, we used Normalized Difference Vegetation Index (NDVI) data and precipitation record for the period from 1982 to 2003 to show the temporal dynamics associated with different landcover types as a function of location along the mean precipitation gradient; and then employed Biome-BGC model to estimate key carbon fluxes and storage pools associated with each of the different landcover classes, as well as the fluxes resulting from landcover changes. Results show an increasing trend of NDVI is from the west to the east, which agreed with the spatial distribution of precipitation, however due to some of LULC types are grown by irrigation, precipitation is not the main effect for vegetation development in west portion. However, overall within the study area, indicated by the temporal distributed plots of wavelet analysis for NDVI and precipitation, vegetation dynamics is obviously affected by long-term regional climatic factors, i.e. precipitation, not by short-term or individual local factors instead. On the other hand, by inputting actual land cover and interpolated meteorological data, as well as important ecosystem variables that govern carbon dynamics, we can better define the impacts of biofuel productions; moreover, this ecosystem carbon cycling simulation by Bio-BGC model illustrates that the extent of those landcover responses depend not only on the rate of changes in local environmental factors, but also on site-specific conditions such as regional climate and soil depth.

Lin, P.; Brunsell, N. A.

2011-12-01

376

Modeling vulnerability of groundwater to pollution under future scenarios of climate change and biofuels-related land use change: a case study in North Dakota, USA.  

PubMed

Modeling groundwater vulnerability to pollution is critical for implementing programs to protect groundwater quality. Most groundwater vulnerability modeling has been based on current hydrogeology and land use conditions. However, groundwater vulnerability is strongly dependent on factors such as depth-to-water, recharge and land use conditions that may change in response to future changes in climate and/or socio-economic conditions. In this research, a modeling framework, which employs three sets of models linked within a geographic information system (GIS) environment, was used to evaluate groundwater pollution risks under future climate and land use changes in North Dakota. The results showed that areas with high vulnerability will expand northward and/or northwestward in Eastern North Dakota under different scenarios. GIS-based models that account for future changes in climate and land use can help decision-makers identify potential future threats to groundwater quality and take early steps to protect this critical resource. PMID:23376514

Li, Ruopu; Merchant, James W

2013-03-01

377

17 CFR 41.25 - Additional conditions for trading for security futures products.  

Code of Federal Regulations, 2013 CFR

17 Commodity and Securities Exchanges 1 2013-04-01 2013-04-01... Additional conditions for trading for security futures products. 41.25 Section 41.25 Commodity and Securities Exchanges COMMODITY FUTURES TRADING...

2013-04-01

378

Biofuels News, Vol. 3, No. 1 (Spring/Summer 2000).  

National Technical Information Service (NTIS)

This is the Newsletter for DOE Biofuels Program. Articles are presented on collection and use of corn stover for bioethanol production, the state workshop program on ethanol, and a subcontract to Genencor for improvement of cellulase enzyme production.

H. Brown

2000-01-01

379

Biofuels News, Vol. 3, No. 1 (Spring/Summer 2000)  

SciTech Connect

This is the Newsletter for DOE Biofuels Program. Articles are presented on collection and use of corn stover for bioethanol production, the state workshop program on ethanol, and a subcontract to Genencor for improvement of cellulase enzyme production.

Brown, H.

2000-08-15

380

Biofuel chain development in Germany: Organisation, opportunities, and challenges  

Microsoft Academic Search

Increasing production activities have been observed in many EU member states since the EU Commission sent a clear signal establishing and supporting the bioenergy industry. This article discusses current sector developments and therewith evolving biofuel value chain activities and management requirements by means of two German biofuel processing firms. Usually, the processing company can be regarded as the initiator of

Kirsti Dautzenberg; Jon Hanf

2008-01-01

381

Biofuels workshop II. Proceedings.  

National Technical Information Service (NTIS)

This publication contains the presentations held in the Biofuels workshop II, arranged by the Finnish Ministry of Trade and Industry and the United States Department of Energy. The scope of the second workshop included all aspects of research and developm...

E. Alakangas

1993-01-01

382

Wind versus Biofuels for Addressing Climate, Health, and Energy  

ScienceCinema

The favored approach today for addressing global warming is to promote a variety of options: biofuels, wind, solar thermal, solar photovoltaic, geothermal, hydroelectric, and nuclear energy and to improve efficiency. However, by far, most emphasis has been on biofuels. It is shown here, though, that current-technology biofuels cannot address global warming and may slightly increase death and illness due to ozone-related air pollution. Future biofuels may theoretically slow global warming, but only temporarily and with the cost of increased air pollution mortality. In both cases, the land required renders biofuels an impractical solution. Recent measurements and statistical analyses of U.S. and world wind power carried out at Stanford University suggest that wind combined with other options can substantially address global warming, air pollution mortality, and energy needs simultaneously.

383

Wind vs. Biofuels: Addressing Climate, Health and Energy  

SciTech Connect

The favored approach today for addressing global warming is to promote a variety of options: biofuels, wind, solar thermal, solar photovoltaic, geothermal, hydroelectric, and nuclear energy and to improve efficiency. However, by far, most emphasis has been on biofuels. It is shown here, though, that current-technology biofuels cannot address global warming and may slightly increase death and illness due to ozone-related air pollution. Future biofuels may theoretically slow global warming, but only temporarily and with the cost of increased air pollution mortality. In both cases, the land required renders biofuels an impractical solution. Recent measurements and statistical analyses of U.S. and world wind power carried out at Stanford University suggest that wind combined with other options can substantially address global warming, air pollution mortality, and energy needs simultaneously.

Professor Mark Jacobson

2007-01-29

384

Thermochemical conversion of biomass to second generation biofuels through integrated process design—A review  

Microsoft Academic Search

The need for clean and environmental friendly fuels is leading the world to the production of biofuels and replacing conventional fuels by them. Second generation biofuels derived from lignocellulosic feedstocks tackle the drawbacks posed by the so-called first generation ones regarding feedstock availability and competition with the food industries. Thermochemical conversion of biomass to biofuels is a promising alternative route

T. Damartzis; A. Zabaniotou

2011-01-01

385

Biofuels and certification. A workshop at the Harvard Kennedy School of Government. Summary report  

Microsoft Academic Search

Liquid biofuels can provide a substitute for fossil fuels in the transportation sector. Many countries have mandated the use of biofuels, by creating targets for their use. If not implemented with care, however, actions that increase biofuel production can put upward pressure on food prices, increase greenhouse gas (GHG) emissions, and exacerbate degradation of land, forest, and water sources. A

Charan Devereaux; Henry Lee

2009-01-01

386

Cyanobacteria and microalgae: a positive prospect for biofuels.  

PubMed

Biofuel-bioenergy production has generated intensive interest due to increased concern regarding limited petroleum-based fuel supplies and their contribution to atmospheric CO2 levels. Biofuel research is not just a matter of finding the right type of biomass and converting it to fuel, but it must also be economically sustainable on large-scale. Several aspects of cyanobacteria and microalgae such as oxygenic photosynthesis, high per-acre productivity, non-food based feedstock, growth on non-productive and non-arable land, utilization of wide variety of water sources (fresh, brackish, seawater and wastewater) and production of valuable co-products along with biofuels have combined to capture the interest of researchers and entrepreneurs. Currently, worldwide biofuels mainly in focus include biohydrogen, bioethanol, biodiesel and biogas. This review focuses on cultivation and harvesting of cyanobacteria and microalgae, possible biofuels and co-products, challenges for cyanobacterial and microalgal biofuels and the approaches of genetic engineering and modifications to increase biofuel production. PMID:21924898

Parmar, Asha; Singh, Niraj Kumar; Pandey, Ashok; Gnansounou, Edgard; Madamwar, Datta

2011-11-01

387

Solar Energy - An Option for Future Energy Production  

ERIC Educational Resources Information Center

Discusses the exponential growth of energy consumption and future consequences. Possible methods of converting solar energy to power such as direct energy conversion, focusing collectors, selective rediation absorbers, ocean thermal gradient, and space solar power are considered. (DF)

Glaser, Peter E.

1972-01-01

388

Hawaii Integrated Biofuels Research Program  

SciTech Connect

Hawaii provides a unique environment for production of biomass resources that can be converted into renewable energy products. The purpose of this work is to evaluate the potential of several biomass resources, including sugarcane, eucalyptus, and leucaena, particularly for utilization in thermochemical conversion processes to produce liquid or gaseous transportation fuels. This research program supports ongoing efforts of the Biofuels and Municipal Solid Waste Technology (BMWT) Program of the Department of Energy (DOE) and has goals that are consistent with BMWT. The Hawaii Natural Energy Institute (HNEI) work completed here consists of research activities that support two of the five renewable fuel cycles being pursued by DOE researchers. The results are directly applicable in the American territories throughout the Pacific Basin and the Caribbean, and also to many parts of the United States and worldwide. The Hawaii Integrated Biofuels Research Program is organized into the following six research tasks, which are presented as appendices in report form: Biomass Resource Assessment and System Modeling (Task 1); Bioenergy Tree Research (Task 2); Breeding, Culture, and Selection of Tropical Grasses for Increased Energy Potential (Task 3); Study of Eucalyptus Plantations for Energy Production in Hawaii (Task 4); Fundamental Solvolysis Research (Task 5); and Effects of Feedstock Composition on Pyrolysis Products (Task 6). 54 refs., 35 figs., 55 tabs.

Takahashi, P.K.

1989-10-01

389

Multi-energy optimized processing: The use of high intensity ultrasonic and electromagnetic radiation for biofuel production processes  

Microsoft Academic Search

This work aimed to improve the understanding of the use of microwaves and ultrasound for chemical processes. Using biodiesel production as the case for study, the non-linear effects of high intensity ultrasonics, electromagnetic loss, and microwave heating were explored. Cavitation and atomization phenomena were used to describe the process of ultrasonic emulsification. The dielectric loss mechanisms pertinent to the biodiesel

Matthew Mason Kropf

2008-01-01

390

Spectroscopic analyses of the biofuels-critical phytochemical coniferyl alcohol and its enzyme-catalyzed oxidation products.  

PubMed

Lignin composition (monolignol types of coniferyl, sinapyl or p-coumaryl alcohol) is causally related to biomass recalcitrance. We describe multiwavelength (220, 228, 240, 250, 260, 290, 295, 300, 310 or 320 nm) absorption spectroscopy of coniferyl alcohol and its laccase- or peroxidase-catalyzed products during real time kinetic, pseudokinetic and endpoint analyses, in optical turn on or turn off modes, under acidic or basic conditions. Reactions in microwell plates and 100 microL volumes demonstrated assay miniaturization and high throughput screening capabilities. Bathochromic and hypsochromic shifts along with hyperchromicity or hypochromicity accompanied enzymatic oxidations by laccase or peroxidase. The limits of detection and quantitation of coniferyl alcohol averaged 2.4 and 7.1 muM respectively, with linear trend lines over 3 to 4 orders of magnitude. Coniferyl alcohol oxidation was evident within 10 minutes or with 0.01 microg/mL laccase and 2 minutes or 0.001 microg/mL peroxidase. Detection limit improved to 1.0 microM coniferyl alcohol with Km of 978.7 +/- 150.7 microM when examined at 260 nm following 30 minutes oxidation with 1.0 microg/mL laccase. Our assays utilized the intrinsic spectroscopic properties of coniferyl alcohol or its oxidation products for enabling detection, without requiring chemical synthesis or modification of the substrate or product(s). These studies facilitate lignin compositional analyses and augment pretreatment strategies for reducing biomass recalcitrance. PMID:19935474

Achyuthan, Komandoor Elayavalli; Adams, Paul David; Simmons, Blake Alexander; Singh, Anup Kumar

2009-01-01

391

Acquainting Future Office Employees with Productivity-Improvement Techniques.  

ERIC Educational Resources Information Center

Examines factors affecting productivity (government regulations, energy costs, decline in the work ethic, capital investment, number of service workers, work force characteristics, management practices, and unions), and techniques to improve productivity (employee involvement, job structure, communication, flexitime, employee upgrading, incentive…

Quible, Zane K.

1982-01-01

392

Natural products and combinatorial chemistry: back to the future  

Microsoft Academic Search

The introduction of high-throughput synthesis and combinatorial chemistry has precipitated a global decline in the screening of natural products by the pharmaceutical industry. Some companies terminated their natural products program, despite the unproven success of the new technologies. This was a premature decision, as natural products have a long history of providing important medicinal agents. Furthermore, they occupy a complementary

Jean-Yves Ortholand; A Ganesan

2004-01-01

393

Aluminum-containing SBA15 as cracking catalyst for the production of biofuel from waste used palm oil  

Microsoft Academic Search

Aluminum-containing SBA-15 mesoporous materials were prepared using two different methods in order to compare their cracking activity in gasoline production from waste used palm oil. The catalyst prepared via direct synthesis (AlSBA) possessed disorder pore size distribution whereas the catalyst prepared via post-synthesis (ACSBA) had narrow pore size distribution. Both the catalysts gave comparable activity but regenerated ACSBA exhibited higher

Yean-Sang Ooi; Subhash Bhatia

2007-01-01

394

Biofuel combustion chemistry: from ethanol to biodiesel.  

PubMed

Biofuels, such as bio-ethanol, bio-butanol, and biodiesel, are of increasing interest as alternatives to petroleum-based transportation fuels because they offer the long-term promise of fuel-source regenerability and reduced climatic impact. Current discussions emphasize the processes to make such alternative fuels and fuel additives, the compatibility of these substances with current fuel-delivery infrastructure and engine performance, and the competition between biofuel and food production. However, the combustion chemistry of the compounds that constitute typical biofuels, including alcohols, ethers, and esters, has not received similar public attention. Herein we highlight some characteristic aspects of the chemical pathways in the combustion of prototypical representatives of potential biofuels. The discussion focuses on the decomposition and oxidation mechanisms and the formation of undesired, harmful, or toxic emissions, with an emphasis on transportation fuels. New insights into the vastly diverse and complex chemical reaction networks of biofuel combustion are enabled by recent experimental investigations and complementary combustion modeling. Understanding key elements of this chemistry is an important step towards the intelligent selection of next-generation alternative fuels. PMID:20446278

Kohse-Höinghaus, Katharina; Osswald, Patrick; Cool, Terrill A; Kasper, Tina; Hansen, Nils; Qi, Fei; Westbrook, Charles K; Westmoreland, Phillip R

2010-05-10

395

Productivity costs in economic evaluations: past, present, future.  

PubMed

Productivity costs occur when the productivity of individuals is affected by illness, treatment, disability or premature death. The objective of this paper was to review past and current developments related to the inclusion, identification, measurement and valuation of productivity costs in economic evaluations. The main debates in the theory and practice of economic evaluations of health technologies described in this review have centred on the questions of whether and how to include productivity costs, especially productivity costs related to paid work. The past few decades have seen important progress in this area. There are important sources of productivity costs other than absenteeism (e.g. presenteeism and multiplier effects in co-workers), but their exact influence on costs remains unclear. Different measurement instruments have been developed over the years, but which instrument provides the most accurate estimates has not been established. Several valuation approaches have been proposed. While empirical research suggests that productivity costs are best included in the cost side of the cost-effectiveness ratio, the jury is still out regarding whether the human capital approach or the friction cost approach is the most appropriate valuation method to do so. Despite the progress and the substantial amount of scientific research, a consensus has not been reached on either the inclusion of productivity costs in economic evaluations or the methods used to produce productivity cost estimates. Such a lack of consensus has likely contributed to ignoring productivity costs in actual economic evaluations and is reflected in variations in national health economic guidelines. Further research is needed to lessen the controversy regarding the estimation of health-related productivity costs. More standardization would increase the comparability and credibility of economic evaluations taking a societal perspective. PMID:23620213

Krol, Marieke; Brouwer, Werner; Rutten, Frans

2013-07-01

396

Biofuels, greenhouse gases and climate change. A review  

Microsoft Academic Search

Biofuels are fuels produced from biomass, mostly in liquid form, within a time frame sufficiently short to consider that their\\u000a feedstock (biomass) can be renewed, contrarily to fossil fuels. This paper reviews the current and future biofuel technologies,\\u000a and their development impacts (including on the climate) within given policy and economic frameworks. Current technologies\\u000a make it possible to provide first

Cécile Bessou; Fabien Ferchaud; Benoît Gabrielle; Bruno Mary

2011-01-01

397

Trading in the future: British Columbia's forest products compromise  

Microsoft Academic Search

The authors examine the commodity?oriented nature of the British Columbia (BC) forest industry in the context of domestic policy changes and globalization. An analysis of primary data on the volume and value of wood products highlights the degree to which BC firms depend on the export of four products (softwood lumber, pulp, newsprint, and paper) for sale in three markets

Cheri Burda; Fred Gale

1998-01-01

398

Engineering microbial biofuel tolerance and export using efflux pumps  

PubMed Central

Many compounds being considered as candidates for advanced biofuels are toxic to microorganisms. This introduces an undesirable trade-off when engineering metabolic pathways for biofuel production because the engineered microbes must balance production against survival. Cellular export systems, such as efflux pumps, provide a direct mechanism for reducing biofuel toxicity. To identify novel biofuel pumps, we used bioinformatics to generate a list of all efflux pumps from sequenced bacterial genomes and prioritized a subset of targets for cloning. The resulting library of 43 pumps was heterologously expressed in Escherichia coli, where we tested it against seven representative biofuels. By using a competitive growth assay, we efficiently distinguished pumps that improved survival. For two of the fuels (n-butanol and isopentanol), none of the pumps improved tolerance. For all other fuels, we identified pumps that restored growth in the presence of biofuel. We then tested a beneficial pump directly in a production strain and demonstrated that it improved biofuel yields. Our findings introduce new tools for engineering production strains and utilize the increasingly large database of sequenced genomes.

Dunlop, Mary J; Dossani, Zain Y; Szmidt, Heather L; Chu, Hou Cheng; Lee, Taek Soon; Keasling, Jay D; Hadi, Masood Z; Mukhopadhyay, Aindrila

2011-01-01

399

[Preface for special issue on biofuels and bioenergy].  

PubMed

Biofuels and bioenergy not only benefit independence of energy supply, but also mitigate CO2 emissions. This special issue includes review reports and research articles involving various biofuels and bioenergy products and systems such as fuel ethanol, biodiesel, biogas, biohydrogen, microbial fuel cells and microbial electrolysis cells. Both fundamental research and technology development are highlighted. And in the meantime, challenges for large scale production and application of biofuels and bioenergy are discussed. Taking advantages of modern biotechnology advances, solutions to address these challenges are envisioned. PMID:20954383

Bai, Fengwu

2010-07-01

400

The Brazilian biofuels industry  

PubMed Central

Ethanol is a biofuel that is used as a replacement for approximately 3% of the fossil-based gasoline consumed in the world today. Most of this biofuel is produced from sugarcane in Brazil and corn in the United States. We present here the rationale for the ethanol program in Brazil, its present 'status' and its perspectives. The environmental benefits of the program, particularly the contribution of ethanol to reducing the emission of greenhouse gases, are discussed, as well as the limitations to its expansion.

Goldemberg, Jose

2008-01-01

401

Jatropha curcas, a biofuel crop: Functional genomics for understanding metabolic pathways and genetic improvement  

PubMed Central

Jatropha curcas is currently attracting much attention as an oilseed crop for biofuel, as Jatropha can grow under climate and soil conditions that are unsuitable for food production. However, little is known about Jatropha, and there are a number of challenges to be overcome. In fact, Jatropha has not really been domesticated; most of the Jatropha accessions are toxic, which renders the seedcake unsuitable for use as animal feed. The seeds of Jatropha contain high levels of polyunsaturated fatty acids, which negatively impact the biofuel quality. Fruiting of Jatropha is fairly continuous, thus increasing costs of harvesting. Therefore, before starting any improvement program using conventional or molecular breeding techniques, understanding gene function and the genome scale of Jatropha are prerequisites. This review presents currently available and relevant information on the latest technologies (genomics, transcriptomics, proteomics and metabolomics) to decipher important metabolic pathways within Jatropha, such as oil and toxin synthesis. Further, it discusses future directions for biotechnological approaches in Jatropha breeding and improvement.

Maghuly, Fatemeh; Laimer, Margit

2013-01-01

402

Future Oil Production for the Alaska North Slope.  

National Technical Information Service (NTIS)

The Alaska North Slope (North Slope or ANS) is the source of approximately 15 percent of United States oil production. It also contains the largest estimated volume of undiscovered petroleum resources of any domestic onshore sedimentary basin. What happen...

2001-01-01

403

Biofuels News--Winter 2001, Vol. 4, No. 1  

SciTech Connect

Newsletter for the DOE Biofuels Program. Articles on collaborative projects with USDA, and OIT. Contains an interview with Doug Kaempf, co-director of the National Biobased Products and Bioenergy Coordination Office.

Tuttle, J.H.

2001-04-16

404

Role of genetically engineered animals in future food production.  

PubMed

Genetically engineered (GE) animals are likely to have an important role in the future in meeting the food demand of a burgeoning global population. There have already been many notable achievements using this technology in livestock, poultry and aquatic species. In particular, the use of RNA interference (RNAi) to produce virus-resistant animals is a rapidly-developing area of research. However, despite the promise of this technology, very few GE animals have been commercialised. This review aims to provide information so that veterinarians and animal health scientists are better able to participate in the debate on GE animals. PMID:23438464

McColl, K A; Clarke, B; Doran, T J

2013-03-01

405

Cellulosic biofuels from crop residue and groundwater extraction in the US Plains: The case of Nebraska.  

PubMed

This study develops a model of crop residue (i.e. stover) supply and derived demand for irrigation water accounting for non-linear effects of soil organic matter on soil's water holding capacity. The model is calibrated for typical conditions in central Nebraska, United States, and identifies potential interactions between water and biofuel policies. The price offered for feedstock by a cost-minimizing plant facing that stover supply response is calculated. Results indicate that as biofuel production volumes increase, soil carbon depletion per unit of biofuel produced decreases. Consumption of groundwater per unit of biofuel produced first decreases and then increases (after a threshold of 363 dam(3) of biofuels per year) due to plants' increased reliance on the extensive margin for additional biomass. The analysis reveals a tension between biofuel and water policies. As biofuel production raises the economic benefits of relaxing water conservation policies (measured by the "shadow price" of water) increase. PMID:24956467

Sesmero, Juan P

2014-11-01