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News and Trends
http://www.tudelft.nl/live/pagina.jsp?id=a466a150-8cb1-4f04-8273-f32af610294e&lang=en Scientists from the Delft University of Technology (TU Delft, the Netherlands) report the introduction of a single bacterial gene into yeast which can achieve three improvements in bioethanol production from agricultural wastes. These three improvements can be described in the following keywords: (1) less acetate, (2) elimination of glycerol by-product, and (3) more ethanol. Pretreated lignocellulosic biomass, prior to ethanol fermentation, is said to contain high amounts of acetate which may adversely affect ethanol production performance in yeast. Glycerol is also one inevitable by-product which can be produced by yeast during ethanol fermentation (about 4% of the sugar is reportedly "lost to formation of the byproduct glycerol"). Both conditions can decrease ethanol yields. According to TU Delft researchers, "yeasts (at least in theory) can convert the harmful acetate to ethanol. However, just one single gene is missing in the yeast. "By introducing a single gene from the bacterium Escherichia coli, researchers of the Netherlands-based Delft University of Technology and the Kluyver Centre for Genomics of Industrial Fermentation enabled this conversion of acetate to ethanol by yeast. This replaced the normal role of glycerol so efficiently that key genes in glycerol production could be removed, thus completely abolishing glycerol production." The researchers hope to collaborate with industrial partners to accelerate industrial application and implementation. Details of their metabolic engineering strategy for ethanol fermentation improvement can be accessed in the journal, Applied and Environmental Microbiology (URL above).
http://www.astmnewsroom.org/default.aspx?pageid=1895 The American Society for Testing and Materials (ASTM) recently released a new standard, ASTM D7566, Specification for Aviation Turbine Fuels Containing Synthesized Hydrocarbons. It "provides criteria for the production, distribution and use of aviation turbine engine fuel produced from coal, natural gas or biomass using the Fischer-Tropsch process". The impetus behind the release of the new standard is the search for alternatives to conventional aviation fuels. According to Mark Rumizen, aviation fuels specialist of the Federal Aviation Administration, and chair of the task group that developed ASTM D7566, "concerns with the future cost and supply of conventionally derived aviation fuel and the imposition of carbon emissions limitations contributed to the development of ASTM D7566". He also said that "the issuance of ASTM D7566 is the culmination of a focused, collaborative effort by the commercial aviation industry to move toward more environmentally friendly fuels, and to diversify the suppliers of aviation fuel". Participation from different sectors involved in aviation fuel infrastructure and biofuel producers for development of future annexes of ASTM D7566 is encouraged.. Energy Crops and Feedstocks for Biofuels Productionhttp://www.thebioenergysite.com/news/5018/new-switchgrass-germplasm-collected-in-florida Switchgrass (Panicum virgatum) is a perennial warm season grass dominating North American prairies/pastures, and is considered as one of the front-running second-generation biofuel feedstocks in the United States. Active research is ongoing for the conversion of switchgrass into cellulose ethanol. The bioenergysite website reports that the United States Department of Agriculture, Agricultural Research Service (USDA-ARS) found 46 new populations of switchgrass in Florida, during collection trips conducted in 2008 and 2009. The researchers discovered new switchgrass populations in many different environments, from swampy areas to dune areas along the coast. Significant genetic variation in the switchgrass populations was also found, including differences in seed maturity, foliage abundance, plant height, and panicle (fruit attached to branch) size. The new switchgrass germpplasm collection will provide new genetic resources for biofuel feedstocks. The materials will be deposited in the ARS National Plant Germplasm System (NPGS), and will be preserved/maintained for future research by plant breeders who are interested in improving switchgrass for biofuel and other applications..
http://www.eurekalert.org/pub_releases/2009-11/f-sf-fay112009.php The Eurekalert website reports two studies by Spanish and Dutch researchers which looked into the production of bioethanol from surplus biomass from the production of flax shives, and from Brassica carinata, "a yellow-flowered plant related to those which engulf fields in spring". The studies, both published in the journal, Renewable and Sustainable Energy Reviews, analyzed the environmental load associated with the different stages of the process: the harvesting of flax or Brassica; (1) the production of ethanol [through enzymatic hydrolysis followed by fermentation and distillation]; (2) blending the ethanol product with petrol [in varying proportions]; and (3) use of the product or its blends in passenger automobiles. The results of both studies show that "the use of ethanol-based fuels can help mitigate climate change by reducing greenhouse gases. However, these fuels also contribute to acidification, eutrophication, the formation of photochemical oxidants and toxicity (for people and the environment)". According to the researchers, the negative effects could be minimized with the use of high-yield crops, through optimisation of agricultural activity and better use of fertilizers.. Biofuels Processing
http://www.biotechnologyforbiofuels.com/content/pdf/1754-6834-2-29.pdf Corn stover is the residue of the corn plant after harvesting which usually consists of the following fractions: leaves, cobs and stock. Corn stover is a good lignocellulosic biomass resource for biofuel (cellulosic ethanol) production. However, each fraction (leaves, corn, stalk) are considered to have different compositions of the following components: cellulose, hemicellulose and lignin. Cellulose and hemicellulose are the polymers which are broken down (i.e., "hydrolyzed" chemically or enzymatically) into simple (ethanol fermentable) sugars, while lignin is the tight wrapping around the cellulose and hemicellulose molecules, which must be removed by thermo-chemical treatment. The relative amounts of these three components affect the intensity of pretreatment conditions (for example, the temperature and dosage of chemicals needed to achieve lignin breakage and the conversion of cellulose/hemicellulose into simple sugars). Furthermore, the composition of the fractions may also vary with the period at which they were harvested (early or late harvest). Scientists from Michigan State University's Biomass Conversion Laboaratory (Department of Chemical Engineering and Materials Science) (United States) attempted to determine whether individual corn stover fractions (both early and late harvests) have different optimal pretreatment conditions. They used ammonia fiber explosion (AFEX), followed by enzymatic hydrolysis as the pretreatment method. Their results showed that the optimal AFEX pretreatment conditions for all corn stover fractions were generally the same, regardless of the harvest period. Details of the study can be accessed in the open access journal, Biotechnology for Biofuels (URL above).. http://www.thebioenergysite.com/news/5017/eu-joins-irena The bioenergysite website reports that the European Union has signed the Statute of the International Renewable Energy Agency (IRENA) in Berlin. IRENA is an intergovernmental organisation with the aim of achieving a rapid transition towards the widespread and sustainable use of renewable energy worldwide. Among its goals are: the creation of a centre of excellence for renewable energy, advising governments on drawing up national programmes for the introduction of these sources, dissemination of information about renewable technologies and implement training activities and advice on best practice and financing options. Since its creation in January 2009, the organization has about 137 member countries, and the EU is its 138th member. According to EU Energy Commissioner, Andris Piebalgs, joining IRENA, the European Union has shown that the promotion of renewable energy sources worldwide is a key element of our external energy policy. With less then a month before Copenhagen, this again underlines that the EU collectively supports a shift away from fossil fuels and towards renewable technologies. Making this shift today rather than later benefits us in terms of the climate, security of supply and also the economy". Related information on IRENA: http://www.irena.org/ |
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