The 2:00 session on Tuesday (2010-4-20) was on lignin modification in order to increase ethanol production efficiency in switchgrass (Panicum virgatum L.). The rationale for researching lignin was that lignin is a structural and physical barrier to polysaccharide degradation and they looked at switchgrass because it is a native species that would not harm biodiversity. Fu, Mielenz, Xiao, Hamilton, Chen, Bouton, Dixon, and Wang used transgenic methods to modify the biosynthesis of lignin and, by this, increase the bioconversion properties in switchgrass. They isolated the primary genes involved with lignin production (using PCR) and found that down regulation of a particular gene resulted in decreased lignin content. This, in turn, improved sugar recovery. They found that a lower S/G ratio was linked with carbohydrate conversion efficiency.
2010-4-20 Session on Lignin modification in Panicum virgatum L. by Fu, Mielenz, Xiao, Hamilton, Chen, Bouton, Dixon, and WangMay 6, 2010
Summary of the 1:00 session on the Genetic dissection of bioenergy traits in Sirghum by Vermerris, Saballos, Kresovich, Murray, Rooney, Pederson, Sattler, and XinMay 6, 2010
There has recently been a substantial amount of research done on sorghum as a biofuel feedstock because of its low water usage and fertilizer requirements. In the first session after lunch on Tuesday April 20, 2010, Vermerris, Saballos, Kresovich, Murray, Rooney, Pederson, Sattler, and Xin research on the genetics of sorghum was presented. They said that Sorghum is best known as a grain crop, but sweet sorghum is very similar to sugar cane in chemical composition. There is also forage sorghum. Sorghum plants are diploid, C-4, annuals that are produced from seeds; they have low-input requirements and a high yield potential. The genome has been sequenced. When sugar production is examined, sorghum “stacks up favorably against sugar cane and switchgrass,” according to the presentor. According to Vermerris et al., the ultimate goal in sustainable biofuel production is to minimize inputs and maximize outputs—this applies to grains, biomass, and sugar. They would ideally like to optimize crops to produce food, fodder, heat, biofuels, and biproducts.They said that sugar accumulation is poorly understood and that it depends on juice volume and cell wall modification. Their research is being done on several groups of Brown Rib Mutants; two of these mutants are the Bmr6 and the Bmr 2 mutants. Of the 19 Bmr mutants, Bmr 2 and Bmr 6 are the most promising for genetic modification. The mutants are being used because they are easier to convert to higher sugar yielding plants. There are 14 different copies of this one particular gene related to sugar production in sorghum, so it has taken them a long time to actually isolate it. Eventually, they succeeded. Vermerris et al. used several mapping techniques and then different cloning techniques in their research. The results will be published later this year.
The 11:00 session on Tuesday (2010-4-20) was about the development of microalgae as a biomass for biofuels. Micro aquatic crops such as duckweed, macroalgae, and microalgae are all currently being researched; this group of researchers, A. Darzins, L. Elliot, L. Laurens, E.J. Wolfrum, and M. Posewitz, is focused on microalgae. They mention the 30 year government study that researched algae based biofuels. This is the same government study that Ian Woertz talks about in his research article on algae based biofuels grown on wastewater streams. The government study ended in 1996. However, the program was essentially revived by the NREL in 2006. This study is continuing the research of that 30 year study. This new projects goal was to isolate and characterize microalgal strains utilizing high throughput techniques. They have research locations in Colorado, New Mexico, and several other locations elsewhere. Freshwater, brackish water, and saline/brine waters were brought back to the lab and they put one alga cell and 1 droplet into 96 well plate and allowed them to propagate themselves. High speed FACS sorting was utilized. They did clonal isolation and then used image positive brightfield microscopy. The green algae were found to be the most prominent, but many were fast growing. They currently think that the water vacuole in diatoms is lipids, but this remains a hypothesis for the time being. They are now working on a “bioprospecting project” using FACS, or florescence activated cell sorting. They are also studying high throughput methods for lipid extraction and identificaltion.
A recent article on Biodiesel Magazine’s website talks about the interaction between the truck-stop/travel plaza industry and the government in regards to the loss of subsidization for biodiesel. The National Association of Truck Stop Operators, NATSO, has sent a letter to several Congressmen, asking them to re-establish the subsidy for producing biodiesel that expired December 31, 2009. Three other groups joined NATSO in this effort: The National Association of Convenience Stores, the Society of Independent Gasoline Marketers of America, and the Petroleum Marketers Association of America. Lisa Mullings, the President of NATSO, claims that these groups are strongly “supporting U.S. environmental efforts.” Mullings says that, unfortunately, travel plazas are unable to make profits without this tax credit. Biodiesel production in the U.S. has dropped by 80% since the government dropped the credit in December. Since the government no longer provides biodiesel manufacturers with the $1/gallon credit, most of these manufacturers have simply added a dollar onto their price at the pump. Thos has led to a decrease in demand for biodiesel because most consumers do not want to pay an extra dollar per gallon when they could buy conventional diesel for less. If the subsidy were renewed, biodiesel production would once again be profitable.
While the truck stop industry is advocating for cleaner burning biofuels, a truck engine manufacturer, Cummins Inc., is now having to pay fines for some engines produced 4 to 12 years ago. According to Biodiesel Magazine, Cummins recently had to pay heavy fines because it failed to put proper emissions equipment on several of its engines produced in the 1998-2006 period. The settlement agreed upon was 2.1 million dollars. A total of 570,000 truck engines were sent to vehicle and equipment manufacturers without sufficient emissions control systems (which had been on the engines when the government tested them). These engines made by Cummins failed to meet the standards of the Clean Air Act. Some missing equipment included parts like diesel particulate filters and diesel oxidation catalysts. Cummins apparently expected the vehicle manufacturers to either make their own or purchase them separately.
On the flip side, a major car company, General Motors, is working together with the United States Department of Energy in an attempt to show that jatropha can produce sufficiently high yields of fuel to serve as a petroleum fuel alternative. Central Salt and Marine Chemicals Research Institute in India is starting two jatropha farms, one will be 39.5 acres in Bhavngar and the other a 93.9 acre plot in Kalol. This research institute is part of th Indian government and is lab-optimizing jatropha for fuel production. G.M. has a plant in Kalol and is supporting this research for their interests in the Indian car market; G.M.’s partnership with the Department of Energy in funding this project is largely due to their mutual interest in maximizing jatropha growth in temperate climates with frosts.
The price of gasoline is predicted to rise to 120 p. per l. within the next week according to the BBC. This is about 1.83 U.S. dollars per litre—about 6 dollars and 93 cents per U.S. gallon. According to the BBC article, the pound’s value is falling at the moment, non-domestic fuel prices are rising, and an additional duty has been placed on fuel. Additional tax incentives have been made there to encourage the purchase of low emission vehicles and duties have been put into effect to decrease the purchase of less fuel efficient vehicles. In the U.K., the current average price of gasoline is 117.93 p l-1 and the current price of diesel is 118.51 p l-1. Although, the additional duty that was added a few days ago is only a single penny increase, there will be two additional increases in duties in October and April. The 3 p increase was supposed to occur all at once; however, Chancellor Darling chose to make the increase tiered. While government revenues should be, in theory, increasing from this duty raise, the government subsidy for the production of biofuel has been eliminated. As a side note, this will also increase petroleum prices because, by government mandate, all petroleum fuel in the United Kingdom contains some percentage of biofuel: this extra increase should amount to around 0.7p.
In April of 2008, Britain passed a law that mandated all diesel and gasoline contain two and a half percent biofuel, which was supposed to be increased to 5% by this year, according to N.P.R. Unfortunately, that increase was postponed. Increases in biofuel content might be difficult for the U.K. Unlike in the U.S., where between 20 and 30 percent of land used for agriculture is used for growing biofuels, the amount of land used for biofuels there is equal to about 2% of farmlands in Europe. Production, though probably less likely to happen now that subsidies have been reduced, has yielded increased revenues for farmers of all crops in Britain. N.P.R. interviewed George Munns, a farmer in England, about the impact biofuel production has had on him. Munns told the reporter that, while he does not grow crops for biofuel production, the increase in biofuel crop prices has positively affected his own revenue from crops. While the government mandated increase of biofuel quantity in petroleum based fuels is certainly good for the environment and for crop farmers in the U.K., the now obsolete subsidy for production of those fuels may not have the most beneficial effects.
Summary of “Extraction of Hydrocarbons from Microalga Botryococcus braunii with Switchable Solvents” by Samori et al.March 25, 2010
In a paper published in Bioresource Technology in 2010, Samori et al. examine a new procedure for extracting hydrocarbons from Botryococcus braunii. Botryococcus braunii is a species of colonial, freshwater, green, microalga that holds high potential as a renewable biofuel source. Samori et al. divide biofuels into first, second, and third generations. According to the authors of this study, ethanol from sugar cane or corn and biodiesel from seeds are considered first generation biofuels; lignocellulosic fuels based fuels are second generation fuels; and, algae/ microalgae based biofuels are the third generation. The rationale behind placing algal fuels at the forefront of biofuel sources lies in algae’s more efficient light usage, ability to grow in otherwise unusable areas, potential to multitask by cleaning up waste water flows, and ease of genetic modifications. Furthermore, biodiesel produced from algae tends to be more readily usable than biodiesel from seed plants. Drawbacks of algal fuel sources include energy intensive harvesting procedures and high economic costs from pond operation and bioreactors according to Samori et al. Despite these hindrances, algae-based biofuels are an upcoming and promising source of energy and as such, should be researched.
One of the most challenging aspects of biofuel production is the extraction of lipids or hydrocarbons from the fuel source. Samori et al. central focus was the comparison of two different SPS systems’ (DBU/ethanol and DBU/octanol), DBU’s, and n-hexane/chloroform/methanol’s lipid extraction efficiencies. An SPS is a switchable-polarity solvent that is based on DBU; DBU is an acronym for 1,8-diazabicyclo-[5.4.0]-undec-7-ene. They found that the alcohol used with the DBU is essential to assembling the liquid carbonate anion. Total hydrocarbon yield was greatest with DBU/octanol (16 ± 2%), second best with DBU alone (15 ± 6%), and third with DBU/ethanol (12 ± 2%); n-hexane yielded only 7.8% (± 3%). All DBU systems posted fatty acid extraction yields in the 0.6 to 0.7% range, while n-hexane/chloroform/methanol yielded around 2.7%. After 4 hours, DBU/octanol and DBU/ethanol yielded similar quantities of hydrocarbons—14% and 13%. The cycle between non-ionic and ionic was done by bubbling CO2 gas through equimolar solutions of DBU/octanol and changing DBU-octylcarbonate salt to its non-polar variant with N2 gas. A hydrocarbon extraction efficiency of 81% was achieved with ionic/ non-ionic cycling. Samori et al. concluded that SPS are promising as a “green technology” for hydrocarbon extraction from dried and aqueous growth microalgal. DBU/octanol had the highest extraction efficiency in both dried and liquid algae samples. SPS are also promising because they serve as a non-hazardous hydrocarbon extraction method for small biofuel production indistries.
Samori, Chiara, Cristian Torri Giulia Samori, Daniele Fabbri, Paola Galletti, Franca Guerrini, Rossella Pistocchi, and Emilio Tagliavin. 2010. “Extraction of hydrocarbons from microalga Botryococcus braunii with switchable solvents.” Bioresource Technology. 3274-3279.
In a recent article for Redorbit Knowledge Network (a science and technology news source), Robert Burns of Texas AgriLife Research informs readers that the genome of Botryococcus braunii, an algae source for biofuel, is being sequenced by DOE’s Joint Genome Institute. Methods and results of the study will be published this summer in the journal of phycology. Dr. Timothy Devarenne and other scientists at AgriLife Research, the University of Tokyo, and the University of Kentucky have been studying this species of algae and focusing specifically on its genetic sequence. They found that Botryococcus braunii has 166.2 (± 2.2) base pairs; mice and men have 3 billion and 3.1 billion base pairs respectively according to Devarenne, so this species of algae has a relatively small genome. However, six other species of green algae have already been sequenced and all have an even smaller genome. The particular genome sequenced of the B race (two other races of Botryococcus braunii exist, but they were not dealt with in the study). The phylogeny of Botryococcus braunii was also examined in the study. Devarenne and the other scientists isolated genes from pure culture by using reverse transcription. The genes were mapped to confirm phylogenetic placement.
Botryococcus braunii holds special interest as a sustainable (or perhaps more accurately, renewable) fuel source. Producing hydrocarbon oil from algae is a relatively easy operation now. What all of these algae have in common as a fuel source is that large quantities of oil can be produced in a small area of land. Most green algae that are used for this purpose, however, produce vegetable oils. However, Botryococcus braunii produces hydrocarbons that are exactly the same as the ones in petroleum based fuels such as gasoline, kerosene, and diesel. Because of this, Devarenne claims that Botryococcus braunii is not technically a biofuel source, but is instead just a fuel source. His argument is furthered by the fact that many coal and oil sources contain oil from this species of algae. Like many other algae, Botryococcus braunii is capable of accumulating 86% of its dry weight in hydrocarbons. The greatest problem with Botryococcus braunii as a fuel source is that it takes about 4 days to double its growth, while other algae species take 6 to 12 hours.