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Doctoral Research and Dissertation

by: Ms. Alene Howell

Doctoral Research and Dissertation FOR 600

Marketplace > University of Idaho > Natural Resource Ecology And Mgmt > FOR 600 > Doctoral Research and Dissertation
Ms. Alene Howell
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This 8 page Class Notes was uploaded by Ms. Alene Howell on Friday October 23, 2015. The Class Notes belongs to FOR 600 at University of Idaho taught by Staff in Fall. Since its upload, it has received 16 views. For similar materials see /class/227832/for-600-university-of-idaho in Natural Resource Ecology And Mgmt at University of Idaho.

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Date Created: 10/23/15
FEATURE Can biofuels finally take center stage Charlotte Schubert Today ethanol and biodiesel are predominantly produced from corn kernels sugarcane or soybean oil But researchers and investors are increasingly upbeat about another biofuel feedstock lignocellulose the most abundant biological material on earth B iodiesel and ethanol despite their surging technical and economic hurdles to produce There s room for improvement in almost popularity as transportation fuels barely ing biofuels from lignocellulose And ifpast every facet of biofuel production from lignoe put a dent in our use of oil But that could oil crises are any indicator political will may cellulose cautious researchers saythe enzymes change The biggest well in biofuels has yet to wither if the price of oil falls are too slow the microbes picky and the breed be tappedilignocellulose the woody part of the plant and a potentially abundant source of Box 1 Show me the money Lignocellulose is everywherewheat straw com husksgt Paine grass discarded rice hung The US government s leadership and investment in bioenergy might trail countries like Brazil Sweden Austria and New Zealand but American investors are by far the world s most bullish on biofuels In just the last several months Silicon Valley s legendary venture capital VC firm Kleiner Perkins Caufield amp Byers launched a 200million fund for investing in bioenergy Several other VC firms in California and Massachusetts have plans to raise funds later this year for financing bioenergy startups Wall Street is smitten too in large part because the share price of Pacific Ethanol Fresno CA USA has tripled in less than a year on the market giving the company a lavish market capitalization of close to 700 millionidespite having no operations As Nature Biotechnologywent to press VeraSun Energy America s second largest ethanol producer along with Hawkeye Holdings and Aventine Renewable Energy were set to float an initial public offering IPO too Equities analysts argue that there has never been a better time to raise capital for bioenergy startups Michael Judd an ethanol analyst at Greenwich Consultants told CNN last month that the spigot is wide open You couldn t find a better time to do an I 0 because margins are probably at the highest they ll ever be he said But Judd and others caution that making money in biofuels is not a straightforward proposition Throughout the world the main driver for bioenergy today are government rules mandating increased biodiesel and ethanol content in diesel and gasoline respectively Other drivers include bans on methyl tert butyl ether a gasoline additive suspected of causing cancer the high price of oil and the quest to gain energy independence The EU mandated that three times more than the current level of 2 of the total energy content of petrol and diesel needs to come from renewable fuels Countries like Thailand are aiming for a 10 renewable mix in the next five years India 20 by 2020 Sweden has stated that it aims to become 100 energy independent by 2020 most cates that 25 OfUS energycome from arable of this independence will come through its own nuclear power but renewable fuels will llandby292539lThe EU has Had forathreemld likely make up the balance According to the US Renewable Fuels Association a trade Increase m bwfud use by 2010 to 575 Of association for the US ethanol industry annual production totaled 39billion gallons last or trees The trick is getting the energy out of it Right now that s an expensive process lime ited to a handful of pilot plants The race is on to optimize the technology that can produce biofuels from lignocellulose sources more ef e cientlyiand biotech companies are in the run ning Table 1 Already several companies and governmentefunded laboratories have engie neered enzymes and microorganisms to optie mize lignocellulose degradation and help turn it into fuel And funding from both the public and private sectors is being ramped up Box 1 The giant oil rm BP London announced in Tune that it would plow 500 million into biofuel research inthe next ten ears In his State of the Union address in January US President George W Bush said that biofue els can help ease the addiction of the United States to foreign oil and he proposed slating 150 million for biofuels as part of his 2007 Advanced Energy Initiative About 140 farm forestry and environmental groups have endorsed the 25 by 25 campaign which advoe 2006 Nature Publishing Group httpiMNwnaturecomnaturebiotechnology m transp rstatioln fuel39 year up 15 from 2004 But estimates indicate that new plants to produce another 19 But 395 sun In 51339 Whather the fund39 billion gallons a year are under construction and will come online by 20 7 mg and lucenthes bemg Offered by govern39 All of this bodes well for biofuels What could possiblego wrong At present less men are suf dent t0 OVercome the major than 1 of the United States fuel stations sell ethanol Only a small fraction of the automobiles sold in America offer flexfuel options Until biofuel and flexfuel vehicles can be purchased just as easily as the oldfashioned variety bioenergy will be constrained Charlotte Schubert is News and Views editor at however Stephan Herrem Editopatiarge ature Medicine NATURE BIOTECHNOLOGY VOLUME 24 NUMBER 7 JULY 2006 777 FEATURE Table 1 Selected biotech companies with biofuel programs Company Location grivida Cambridge MA iunoi Ce Dedham MA USA Ceres Thousand Oaks CA USA Direvo Cologne Germany Diversa San Diego Dyadic Jupiter FL USA Edenspace Systems Dulles VA USA Genencor subsidiary of Danisco Paio Alto CA USA GreenEuei Technologies Cambridge MA USA iogen OttaWa ON Canada Linnaeus Piant Sciences Vancouver BC Canada Mascoma Cambridge MA USA Monsanto St Louis Novozymes Bagwaerd Denmark SWeTree Umea Sweden Syngenta sei Biotec Guiiford UK w 2006 Nature Publishing Group httpiMNViLnaturecomnaturebiotechnology Focus Engineering corn to produce enzymes for making ethanoi postrharvest Has buiit piiot ceiiuiosic ethanoi facility developing plans for a iargerscaie piant Engineers Escherichia coi to ferment all types of sugars released from cellulose to ethanol licensed from U Florida Deveioping energy crops sWitchgrass for ceiiuiosic energy improving costreffectiveness of ethanol production from iignoceiiuiose through directed evolution Enzymes for converting ceiiuiosic biomass to fermentabie sugars termiterderived enzymes in coiiaboration With DOE and Caitech enzymes for increasing efficiency of biodiesei Equityfunded startrup With grantsfrom the US Small Business innovation Research Program Mass Tech Collaborative and ReneWabie Energy Trust Equityrfunded startup formerly BC international 133 77miiii0fi licensing deal With Monsanto 197miiiion in privatefunding Pubiiciytraded on Nasdaq market cap 503 M Participates in integrated Cornrbased Refinery Program Markets orramyiase for grain ethanoi by Vaiiey Research Proprietary piatform for discovering developing and manufacr Pubiiciytraded on Nasdaq market cap 137 M turing novei genesfrom diverse organisms in collaboration With ioWa Corn Promotion Board in DOErfun ed program Deveioping corn sWitchgrass and other crops as ceiiiosic ethanoifeedstocks Phytoremediation services Protein and pathWay engineeringSells enzymes for pulp fabric and other industries Aigae bioreactor for recyciing C02 and converting to high energy biomass Manufactures enzymes in paper textile and animal feed Has demonstration piant for converting biomass to ceiiuiosic ethanoi Engineering piantsto make oiisthat can replace petroleum products Biomass to ceiiuiosic ethanoi designing ceiiuiosic ethanol plant Crop anaiytics program for identifying corn With higher extractable starch soybeans With high oil and protein content Producer of industrial enzymes and microbes produces enzymesfor reducing viscosity of piant mash Popuus trchocarpa expressed sequence tag and functional 2005 revenues 11 million 750 K Research aiiiances With NREL USDA Michigan State 17 million from NRELfor ioW cost ceiiuiases12 miiiion from French government for making ethanol from paper pulp PartnershipWith NRG Energy NY 8 million in Series B Polaris Waitham MA USA 130 million in private investment 54 Canadianfrom Royai DutchSheii Group 30 million Goldman Sachs 15 5 from PetroCanada 10 million from Technoiogy Partners Canaca Muitiryear RampD agreement With Atofina Paris 4 million in privatefunding Pubiiciy traded on NeW York Stock Exchange NYSE Market cap 21 billion Pubiiciytraded on Copenhagen Stock Exchange 15 million from US DOE for ioWrcost ceiiuiases Joint venture With intellectual property holder Woodheads genomics program and fungi that dramatically increasethe prorUmea SWeden 1 million in seed fundingfrom duction of ethanol from agricuiturai and forest Waste Deveioping corn expressing high levels of amyiaserT Deveioping thermophiiic microorganisms to replace yeast in ethanol fermentation Organism capable of fermenting both C5 and C5 sugars Teknikbrostfteisen Umea SWeden and 2 2 million from Kempestifteisen Ornskoidwik SWeden Pubiiciytraded on NYSE Market cap 13 billion Partnering With six for share of 57miiii0fi research grant rom EU ingprograms for specially tailored crops still in their early stages Experts disagree about when facilities to convert lignocellulose to fuel will operate on an industrial scale fit may be five years or ten or twenty But all agree that bringing down costs will be key Back to the future When Henry Ford built his first car the quad ricycle in 1896 he designed it to run on ethae nol in Germany Rudolph Diesel built his engines to run on peanut oil Althoughthe rst attempts at drilling rock oil to supplant these biofuels met with skepticism the consumption of petroleum inevitably surged with the rise of the automo ile Over the past few decades as fossil fuel use has continued to climb researchers in academia Midwest US automakers are making specially tooled exefuel cars to run on the same mix A J J and government rat Vi 1m b work ing on converting biomass to fueliwith little attention or funding Now as oil prices begin to scale unprecedented heights alternative fuels are again on the political agenda Swarms investors consultants and press are buzzing around biofuel technology Biofuels are fashe ionable again Worldwide production of biodiesel increased by 60 in 2005 and ethanol by 19 over the previous year s production according to the Worldwatch Institute a research organization in Washington DC Gas stations selling 85 t o H ethanol blends r 1 1 r VOLUME 24 NUMBER 7 r sell biofuels are locking into place worldwide see Fig 1 A allon of corn ethanol in the United States costs about 100 to produce and contains about 70 the energy in a gallon of gasoline Massive agricultural subsidies and a 51 ecent ethanol tax credit keeps the fuel owing Some of the rise of bioethanol in political circles has been attributed to the intensive political lobby ing of agribusiness giants like Archer Daniels Midland ADM Decatur IL USA which has a vested interest in boosting ethanol to main t 39 L 39139 A 139 enterfor JULY 2006 NATURE BIOTECHNOLOGY Responsive Politics httpwwwopensecrets paid politir 990 d mparison the oil and gas industry donated only182 million No one knows exactly how ya an expansion ln cl and us ce fuel costsor affect the economyat largeAnd it may not be the most enyironmentallyf iendly option The US EnVironmental Protection ency PAforexamplehasacknowleclgecl thathighvolatiliryofethanoi in gasoline blends under 10 ethanol can lower air quallty and lncreasesmogr From corn to Iignocellulose Most biofuels todaycome from the starchy and fruits are not nearly as abundant as llgnocelr bed biomass heUSDepartment n from lignocellulose which the DOE expects will become cheaper to make as the technolr o im royes Researchers at the US Natlonal Renewable la n ing facility which would yield 507mllllon gale threert grain ethanol plant with gions ofethanol per yeariat 215 miliionabout o fourfold more expensive than a come e yi the 3am lcl And nocellulose to ethanol is estimated to consum 70 of the cost and raw materials 30 the exact opposite ofoil refining today We have a lot ofroom 0 move to k ur competitive he said at the 23th Symposium on Biotechnology for Fuels and Chemicals in Nashyille this Apri r The production process People have been converting fruits and grains a ntatlon for thousands he process hasn t chan ed much In ethanol production facilitiessugars NATURE BIOTECHNOLOGV VOLUME NUMBEK7 lulvzooe FEATURE Biuelhanol and enzyme market growth 30000 Us w vld Enzyme markei 25000 3 c E a 20000 395 E 3 15000 g e E 5 10000 5 g iu 5000 0 1980 I935 930 995 2000 ZUDS 2am 205 2020 Year Flgure 1 Rising production of blofuels Source Renewable Fuels Association Washington DC and starches are turned into ethanol in a few pletyplcallyconslstsof4t 50cellulose25 t t lw v vn simple steps In the wit a wi h an enzyme that helps convert the starch One a proach to extract fuel from llgnor into sugar and then yeast ferments the sugar cellulose borrows technology from the coal into ethano1Fi 2 and oil industry to convert plant material Whereasstarchissoftlignocellulosethemain into syngas mainly carbon monoxide and la l it h rlv n W a l th n A L resist degradation It consists of mostly hemir ulose and celluloaegglucose chains stacked H L r to nol or biodiesel by the FischerrTropsch pror cess anented in Germany in the early 1900s n th v r Tl Hm nm b n mil rmthellmt a 7 tr to produce celr wateror n m t t lHl l L L Wood fr m lulosicethanoltFlg3 Conventortal ethanol production prooe Alcohol Thermorstable mode alphaarnylase Glucoamylase Veas 39y quuetactlon Sacchavltlcatlon Dtstllattomdewmatton Fermentation w mimntstvsala mistan FlgureZ Steps in the process for maklngethanol DDGS dlstllleddrled grains with solubles Source Genertcor FEATURE r Biomass to sugars ermentation of sugars 1 F ue wager molecules cellulosIcs syngas FisherTropsch j y or othe r platform conversion Figure3 The two processes for producing ethanol from biomass biological conversion top and via syngas bottom Only a few pilot plants have been built to produce cellulosic ethanol The largest such plant is run by Iogen an Ottawaebased private biotech company The facility is designed to churn out about 260000 gallons a year from 3200 tons of straw Like similar schemes the Iogen facility is built around a multiestep pror cess a harsh pretreatment step such as high temperature and acid breaks apart the basic structure of lignocellulose melting the crys tals of cellulose Then enzymes convert the exposed cellulose into sugars Finally yeast is used to ferment the sugar into ethanol What s left is clumps of higheenergy lignin which is resistant to fermentation Most designs call for lignin combustionto provide electricity to power the plant Cellulases and strain development To make the designs for cellulosic ethanol facilities more ef cient engineers are shaving costs from pretreatment and other steps And biolog ists are focusing ontwo hurdles that have plagued the technology for decadesithe high cost of cellulases the enzymes that break down cellulose and the limited ability of the microbes to ferment the breakdown products Iogenuses its own proprietary cellulases and is laying the plans for a 307millionegallonepere year facility with partners such as Royal Dutch Shell Oil London and The Hague and Petroe Canada Calgary AB Canada Two other enzyIne biotech companies supported by large grants from the DOE have brought down the costs of the enzymes Genencor International Palo Alto CA USA and the Danish come pany Novozymes Bagsvaerd Denmark have reduced the cost of cellulases about 20 fold to about 15720 cents per gallon according to NREL That s still expensive according to Mike Himmel a biochemist at NREL By compari son amylase one of the enzymes that breaks 2006 Nature Publishing Group httpMNWnaturecomnaturebiotechnology down corn starch for fermentation costs 274 cents per gallon Cellulases are less than ideal in other respects as well Cellulases do their job very slowly and at atime scale not very compatible with large scale plants They are probably good enough now to initiate demonstration plants but prob ably not good enough to meet these longeterm goals says Himmel Skeptics are waiting to see if the claims for the Genencor and Novozyme enzymes hold up in larger facilities Novozyme cellulases for instance will be used in a cellulosic ethae nol plant being planned as an addeon to an existing Spanish ethanol facility by Abengoa Bioenergy a multinational ethanol company based in Seville Spain Meanwhile other researchers aim to over come the limited diet of yeast Yeast fermentae tion breaks down glucose and other hexoses but not the pentoses that result from the breakdown of hemicellulose which comprises 15750 of lignocellulose depending on the type of plant Lonnie Ingram a University of Florida Gainesville microbiologist has cree Box 2 Fuels bloom from algae ated strains of Escherichia 501139 that break down both hexoses and pentoses into ethanol during fermentation which he has licensed to Celunol Corporation Dedham MA USA He s also created an E coli strain that can turn these suge ars into organic acids used in plastics which demonstrates the versatility of products that could be ma e from biomass Nancy Ho and colleagues at Purdue University West Lafayette IN USA have engie neered a yeast strain to ferment both glucose and xylose the main component of hemicelr lulose They have licensed their yeast strain to Iogen and other companies Companies are tight lipped about improve ments to their microbes but some researchers caution such strains can suffer from draw backsisuch as susceptibility to inhibitors in bioreactors Such problems can be ameliorated with changes in engineering and pretreatment processes say Purdue researchers Meanwhile some microbiologists dram even biggeriof the do fall microbe that diews up cele Most biofuel producers focus on extracting as much energy as they can from terrestrial plants like corn and sugarcane but a handful of researchers and entrepreneurs have their eye on an aquatic sourcealgae Isaac Berzin once built bioreactors for experim ents on the international space station as an engineer at the Massachusetts Institute of Technology MIT Cambridge MA USA But in his spare time he built another kind of reactor on the roof of the MIT power plant The reactor captures greenhouse gas emissions like carbon dioxide from the power plant and feeds them to algae growing in transparent tubes exposed to sunlight The algae are then harvested the oils extracted and turned into biodiesel Berzin is now the chief technology officer of GreenFuel Technologies Cambridge MA USA which is buildinga demonstration project in the sunny southwest United States this summer The advantage of algae says Berzin is their sheer output Singlecelled algae can divide every few hours much faster than any terrestrial crop Algae are the fastest growing plants on earth he says Algae are not bananas He claims his systems can produce 20000 gallons of fuel per acre every year about 40 times as much fuel as an acre of corn grain yields Depending on how they are processed algae could yield biodiesel ethanol and other types of products Berzin is not alone in his enthusiasm We are pretty bullish on it says EricJarvis a senior scientist at the National Renewable Energy Laboratory Golden CO USA NREL shut down its algaetofuels research program about ten years ago because of tight budgets and a move toward biomass Now with high oil prices and interest in biofuels growing We are getting calls all the time from investors and energy companies There is an incredible amount of interest Afew other companies have licensed similar technologies including GreenShift an energy company based in New York City Jarvis thinks it is time for NREL to revive its algae program He says there s lots more room for honing the designs of bioreactors learning more about the algae and streamlining genetic engineering systems It s an immature technology says Jarvis You are not going to put a plant on the ground and be profitable in a number of years But it sworth pursuing says Jarvis He notes that algae will not displace food crops as with some biofuels And they scrub power plant emissions The MIT system captures 40 of the carbon dioxide output and 86 of the more powerful greenhouse gas nitrous oxide Jarvis says he s impressed with Berzin s designs but he is concerned about the capital costs Berzin will not reveal the costs but he notes that Greenfuel has raised 20 million in venture capital This is not a charity effort he says They want to make money VOLUME 24 NUMBER 7 JULY 2006 NATURE BIOTECHNOLOGY 2006 Nature Publishing Group httpwwwnaturecomnaturebiotechnology lulose ferments hexoses and pentoses and spits out ethanol That could reduce the number 0 steps required to produce cellulosic ethanol and drive down the cost But such a bug is a complex taskgcelluloseeconsuming bacteria are different than the yeast that ferment sugar into ethanol Moreover genersplicing technology has only just emerged for some of the unusual microbes that degrade cellulose Undaunted Lee Lynd at Dartmouth College Hanover NH US and his colleagues have engineered both yeast and a thermophilic bace teriumto chew up cellulose and make ethanol albeit at low yields and 39 L 39 39 39 for instance the yeast still does not ferment pen toses Lynd says he and others in the eld could have an industryeready microbe ready within a few years but he concedes that other research ers are not so sanguine The president says this out of the blue and everyone says this is going to happen but we haven t really even set the table yet says Iared Leadbetter a microbial ecologist at the California Institute of Technology Pasadena CA USA Leadbetter and Himmel emphasize the need for more basic research into lignocele lulose a substance scientists are onlybeginning to understan Himmel and other biochemists focus on the basic biochemistry of cellulases with the aim of one day engineering one better than any theyhave seen in nature Leadbetter searches for a better tool chest of enzymes turning to the world s lignocellulose experts wood chomping termites To harvest his favorite species in Costa Rica he has to dodge fragrant terpines sprayed from a nozzle in their heads when they get angry To get at the microbes gin their guts Leadbetter and his colleagues spend days chopping open the insects and extracting tiny drops of intestinal liquid After the termites chew wood microbes in the gut break down the wood into acetate which nourishes the insects Leadbetter is now characterizing the metagenome of the microbial community in partnership with Diversa San Diego CA USA and colleagues at the National Biodiversity Institute in Santo Domingo de Heredia Costa Rica Leadbetter presented preliminary ndings at a meeting sponsored by the GenomesetoeLife program at the DOE in February 2006 He has identi ed sequences for more than a hundred potentially useful enzymes that break down wood including hemicellulases and enzymes that process pentoses But getting themto work in a bioreactor or an engineered microbe is another challenge You probably need several dozen enzymes to degrade wood and they all have to work effectively stably and as rapidly as possible he says NATURE BIOTECHNOLOGY VOLUME 24 NUMBER 7 FEATURE Box 3 Biofuel cellulosic feedstocks Most researchers envision that corn stover will be the firstgeneration cellulosic ethanol crop in the USiin part because of its massive acreage and to interface with existing ethanol producers But few experts seem to regard corn stover as ideal in part because it s tough on the environment Perennials such as poplar and switchgrass are less damaging Compared with corn switchgrass cultivation results in oneeighth the nitrogen runoff and one hundredth less soil erosion The prairie grass has a big root system that adds carbon to the soil instead of depleting it Birds also like to live in the stuf Switchgrass also has a lot of energy locked into it Currently yields are about 4 tons per acre and current cellulosic ethanol technologies produce yields of about 75 gallons per ton says Dale In the future breeding programs could at least double switchgrass yields and increase ethanol output to about 100 gallons per ton says Michael Ladisch director of L L engineering lab at Purdue University West Lafayette IN USA But some researchers suggest avoiding a fixation on monocultures altogether Studies on prairie grasses have found that they thrive when species are interplanted interacting to provide nutrients to each other and use up every available ecological niche D avid Tilman at the University of Minnesota and his colleagues found that plots with high plant diversity had 180 more biomass than monocultures such as switchgrass and they were better able to fend off insults such as drought3 The key to high yields may be to find the right plant mixture he suggests Once you plant these things they take care of themselves I have seen prairie grass in Kansas that has been mowed for hay every single year for 100 years and it s still highly productive says Tilman Biology or chemistry Some engineering companies and investors particularly in Europe are turning to another strategy They are honing the technology for 1 I I 1quot 1 Bullish on biomass Regardless of the technology or feedstocks Box 3 used to produce biofuel changes to crops and how they are grown has the potential 1 1 the same engineering principles that turn coal into liquid fuel from syngas But the process is still not cheap and easy Biomass is messier than coal and gums up the facilities with tarry substances reducing yield The estimates for a fullrscale facility range from 903007400 million according to lens Riese who leads the indus trial biotech group at McKinsey and Company Munich a managementeconsulting firm Riese admires scenarios that call for a set of interlocking facilities hooked up to nearby cropland and transportation networks With the profits from a conventional biodiesel plant which costs 20730 million to build smaller investors can nance a conventional or cele lulosic ethanol plant he says And eventually they could add on a 39 facilitvto extract transportation fuel and other products out of the remaining lignin or from allepure pose biomass There are people who believe that syngas technology has stronger prospects than cellue losic ethanol conversion says Riese pointing out it has advantages like easier adaptability to different types of plant material Riese says it s unclear which technology will prevail I think the jury is still out he says Other researchers hold out for even more fantastic technologiesifor instance bacteria that convert biomass into hydrogen and algae that yield biodiesel Box 2 JULY 2006 increasing yields growing them on marginal soil or designing crops to melt more easily in a biofuel facility Corn stover the stalks and other inedible parts left on the eld after harvest could provide the test fuel for the earliest cele lulosic ethanol facilities say US researchers The reasons are both political and logistie cal Big ethanol producers such as Archer Daniels Midland which produces 2573 0 of the country s ethanol operate comfortably and profitablyiand building facilities to con vert biomass to ethanol currently carries huge nanc39 risks To reduce this risk researchers at NREL envision cellulosic ethanol facilities plugged onto existing corn grain ethanol facili ties and their associated farming and trans pnrtafinn 39 e proponents of lignocellulose must work carefully with those who are involved in cornstarch production says Himmel We want this to be an effective alliance But corn stover alone will not yield enough biomass to even come close to the ambir tious DOE targets And as Alex Farrell at the University of California Berkeley puts it Corn is not the ideal crop inpart because of its envi ronmental footprint Box 3 Experts envision that dedicated biofuel crops will eventually become popular These will be unique to a region s climate and soil such as the more environmentally friendly poplar and FEATURE switchgrass a prairie perennial or mixtures of species Several scenarios for cranking up the biomass output of the United States have been released including the Billion Ton study in 2005 by the DOE and the US Department of Agriculture USDA Box 4 The study concluded that biomass available for biofuels on US agriculture and forestlands could increase more than four fold by 20307read1ing 1 3 billion tons enough for more than 60 billion gallons of ethanol Corn stover is a part of that scenario but the study also hinges on several assumptions about the future These includes a doubling of the biomass yield of dedicated biofuel crops like switchgrass to about eight tons per acre enough ethanol for 600 gallons with today s conversiontechnology That may seem ambie tious but many experts are optimistic In some ways this is a conservative pre diction says Brian Davison director of bio processing research at Oak Ridge National Laboratory Oak Ridge TN USA We are not there now but the assumptions sort of fall under the research as usual should get us there category Plant geneticists point out that during thou sands of years of breeding crops have not been selected for high biomass So there s still a lot of genetic variation available for breeders to work with The rst generation of biofuel feed stocks will emerge from conventional breeding or breeding assisted by molecular markers say experts At the recent Nashville meeting for instance Lawrence Smart and his colleagues at the State University of New York Syracuse reported that they had increased the biomass 90f shrub willow by about 40 after one gener7 ation of conventional breeding and selection 2006 Nature Publishing Group httpwwwnaturecomnaturebiotechnology In addition to agrochemical giants such as Dupont Wilmington DE USA several biotech companies are also perfecting plants for biomass In Na hville r m h r at Ceres Thousand Oaks CA reported that they had identi ed an array of genes inArabidopsis thalie and that boost biomass increase nitrogeneuse ef ciency and increase resistance to the stress of drought cold or salt Ceres has a1377mile lion licensing agreement with Monsanto St Louis MO USA to characterize genes for new varieties of traditional row crops like corn and soybean and they have a molecular marker7 based breeding pro ran for switchgrass with the Samuel Roberts Noble Foundation Ardmore OK USA a nonprofit agricultural organization Some companies including Ceres and Edenspace Systems Dulles VA USA are also engineering crops to produce their own induce ible cellulasesSud1 plants say resmrchers could help overcome the cellulase problem plaguing the enzyme scientists Plants with lower lignin content are also being developed and they might also be easier to process in a cellulosic ethanol facilityibut there is some concern that structural integrity could be compromised ecological invasiveness could be increase or soil microbe communities might be alteredl In the near term many plant biologists focus on more conventional biofuel goalsisuch as squeezing more oil from soybeans or sugar from sugarcane Syngenta Basel is testing the regulatory waters for biofuels with a corn plant that could be processed more easily in a conventional corn grain ethanol facility The corn produces its own amylase to accelerate the breakdown of starch and is queued up with regulatory agencies in the United States Box 4 How ecofriendly are biofuels The acolytes of biofuels tout them as the ecologically conscious alternative to fossil fuel and proclaim allegiance to the p anet in boardroom conversations hippie chatrooms and on bumper stickers The fuels seem to fit nicely into the carbon cyclebeing manufactured from plants which suck up atmospheric carbon But are biofuels really a guiltfree elixir to ease our environmental woes Anyone who says that biofuels are greenhousegas neutral is wrong said biofuels expert Bruce Dale at the 28 h Symposium on Biotechnology for Fuels and Chemicals this April in Nashville Tennessee Dale is professor of chemical engineering at Michigan State University East Lansing He goes on to say We will probably have to apply better management practices so they will be more greenhouse gas effec Ive The environmental benefits of biofuel hinges on its source how the plants are farmed and harvested how the fuel is extracted and how the fuel isfinally blended Numerous studies of corn grain ethanol for instance conclude that its greenhouse gas benefits are VOLUME 24 NUMBER 7 Crops like switchgrass will be grown in the same regions as native plants increasing safety concerns about genes hopping species 39 cu iueeredplants Butplants engineered for lignocelluloseetoefuel conver7 sion are years away leaving time to develop technology to prevent cross breeding says Nathanael Greene a senior policy analyst at the National Resources Defense Council in New York City We are long way off from where we as a society will need to tackle the GMO genetie cally modi ed organism crop issue for biofue els says Greene I think it will be a nonissue when it comes to that time Infrastructure While biologists meddle with nature s designs engineers ready theirs The best way to learn is actually to go out and build and do said Andrew Richard in Nashville Richard is a vice president of the SunOpta BioProcess Group Toronto which is providing components for a cellulosic ethanol facility in Spain with Abengoa And these are just two companies drawing up blueprints Following a directive in the 2005 Energy PolicyAct the DOE has issued a call for propose als for up to three largeescale facilities that con vert biomass to fuel or another useful products The DOE will cover 40 up to 80 million of the cost of a new plantibut it must be pro t able and replicable Researchers at NREL saythat such incentives are necessary to help overcome the nancial risks of pioneering new technology but they emphasize the importance of getting it right a big op could put a chill onbiomass Because of that concern before the 2005 Energy Bill the DOE had envisioned more marginalibut that s with today s way of manufacturing it And if you switch the plant source from intensively farmed corn grain to biomass the resulting fuel has high greenhouse gas benefitsiand it takes less fossil fuel energy to produce Such cellulosic ethanol also could leave a smaller footprint on the land air and wateribut that depends on how it s made Researchers who conduct lifecycle studies examine inputs such as fertilizers and transport and they stack that up against the energy contained in the resulting fuel These analyses yield numbers for net energy gains and greenhouse gas emissions Biofuels have the potential to put a dent in both transportation comprises 23 of the world s energy use and emits 28 of greenhouse gases in the US according to the Worldwatch Institute in Washington DC and the Natural Resources Defense Council NRDC based in New York City Alex Farrell an energy researcher at the University of California Berkeley and his colleagues recently took stock of several lifecycle studies for corn grain ethanol2 Adding upthe fossil energy inputs JULY 2006 NATURE BIOTECHNOLOGY w 2006 Nature Publishing Group httpwwwnaturecomnaturebiotechnology Box4 con nued of petroleum coal and natural gas resulted in 4 joules of energy produced from ethanol for every 3 joules of energy used2 That s a fairly slim net positive fossil energy ratio of 133 What s more per mile driven corn ethanol produces only 13 fewer greenhouse gas emissions than gasolineand Farrell says there is great uncertainty in that number Fig 4 The main reason for the poor greenhouse gas benefits of corn grain ethanol is the massive amount of nitrogen fertilizers applied to corn fields These fertilizers are produced largely from natural gas and are transformed by microbes into nitrous oxide a powerful greenhouse gas In addition it s difficult to quantify this effect which depends a lot on farming practices Although this and similar studies seem to tug the green label off of corn some researchers have been trying to yank it off David Pimental an agriculture expert at Cornell University Ithaca NY USA and his colleagues are well known for their view that corn ethanol has a net negative fossil energy ratio and greenhouse gas contribution Most other researchers dispute Pi mental s conclusions claiming he used outdated inputs and factors that others ignorei such as the energy consumed by farm laborers or the fuel used to make farming equipment and production facilities Pimental s conclusions clearly lie outside the norm of numerous studies by labs in academia government and nonprofit institutes But even those who vehemently disagree with Pimentaliand that is many others who conduct lifecycle analysesiadmit that tweaking the numbers here and there with different inputs could tip the balance Almost every lifecycle analysis is missing something When the differential is 30 or 40 it s easy to play with the statistics to push the number to the positive or negative side says John Sheehan at NREL One particularly robust number for corn grain ethanol is the percent reduction in petroleum use says Sheehan Per mile driven grain ethanol uses 807 9O o less oil than gasoline he says That s because corn ethanol uses mainly coal and natural gas in its production Critics note that this equation largely displaces one nonrenewable energy source with another but ethanol boosters note that the tradeoff reduces petroleum consumption and reliance on foreign oil While the green tinge of bioethanol yellows Willie Nelson and other advocates are singing the praises of biodiesel The country singer has his own brand of biofuel BioWillie made from vegetable oil Lifecycle studies give vegetable oil biodiesel a fossil energy ration of between 2 and 3 Estimates of greenhouse gas reductions also vary but cluster between 40770 30 savings over conventional diesel per mile driven That s because biodiesel requires less nonrenewable energy to manufacture than ethanol And the most popular source of biodiesel in the US soybeans fixes its own nitrogen and so requires less fertilizer But soybeans yield about a sixth as much fuel per acre as corn ethanol according to Worldwatch None of the fuels we have today are barely any good Never mind ideal says Farrell Farrell points out that lifecycle analyses fail to take into account many of the environmental drawbacks of biofuels such as soil erosion and water consumption Seventy million acres in the US are devoted to corn715 o 0 which goes to ethanol productioniand the agricultural runoff into the Mississippi River chokes off oxygen supplies and helps create a New Jerseysized dead zone in the middle of the Gulf of Mexico each summer NATURE BIOTECHNOLOGY VOLUME 24 NUMBER 7 NW 2006 FEATURE Farrell is not sure cellulosic ethanol will be the ultimate fuel sourcebut it certainly wins out in the lifecycle assessments Most fossil energy ratios for cellulosic ethanol range from about 4710 and greenhouse gas reductions hover around 85 he major reason for the energy and greenhouse savings of cellulosic ethanol is that the lifecycle analyses factor in the energy savings of powering the ethanol plant with lignin a byproduct of biomasstofuel conversion Most designs call for this power source instead of the natural gas that fires most ethanol plants today Without this factor the energy savings of cellulosic ethanol drops substantially but taking out lignin totally misses the boat says Nathanael Greene a policy analyst at the NRDC Another reason for the favorable lifecycle assessments of cellulosic ethanol is that biomass is expected to yield more ethanol per acre Although corn yields vary greatly Dale estimates that an average acre results in 430 gallons of grain ethano harvest half the stover about the amount reasonable with current methods convert that to ethanol and you would get an extra 150 gallons High biomass crops like switchgrass also require less fossil fuel input than corn upping the net energy yields Because cellulosic ethanol technology is not mature researchers admit the lifecycle estimates are best guesses For instance Hosein Shapouri an economist at the USDA says that he can obtain similar greenhouse and fuel savings if he assumes that waste biomass is burned to power existing ethanol facilities On the other hand scenarios factoring in improved technologiesisuch as higher biomass yields and more efficient ethanol manufacturing technologyican crank up the energy and greenhouse gas benefits even higher for cellulosic ethanol Whether cellulosic ethanol wins out in these and other measures of environmental impact depends on how the technology is implemented Cellulosic ethanol can contribute to our energy and environment goals if we do it correctly and the issue is if we are going to do it correctly and how much land are we going to do it correctly on says Farrell CS Biodiesel Com so beans 9i rapeseed Biodiesel am i ethanol canola Cellulose Sugarcane wase ethanol ethanol cookingoil 750 400 gure4 Approximate greenhouse gas saVings With biofuels The percentage of greenhouse gas emissions displaced by driVing a unit distance using biofuel instead of conventional fuel Each crop is compared to the appropriate fuel ethanol to gasoline biodiesel to diesel Source Worldwatch lnstitute and Argonne National Laboratory reference 2 2006 Nature Publishing Group httpwwwnaturecomnaturebiotechnology FEATURE modest plans to help underwrite apilot project according to Gene Petersen a project manager at DOE We were not feeling there was enough maturity in the technology out there but maybe we are being proven wrong says Petersen Now he anticipates a solid lineup of innovative applie cations by the deadline in August iand like other researchers at DOE awaits the nal pror posals before passing judgment onwhether the plants are likely to be pro table With such projects the US government contributes substantially more money for biomass RampD than the European Union and other countries according to McKinsey s Riese In 2003the EU spent only20 million he says whereas biomass budget at the DOE alone was 90 million and other agencies like the USDA also kick in President Bush s 150 million request for 2007 is a 60 increase over the 2006 DOE biomass and biofuels budgeti although he s also asked for cuts in other DOE budgets such as industrial and automobile efficiency And money earmarked for congressional pet proj ects ate up more than half of the DOE biomass budget last yearisuch as a 17mjllion project in Ohio to make cement with the energy from burning discarded roo ng shingles made from asphalt Biomass advocates say that even with the budget boost the biomass budget is less than half that already authorized by Congress in the 2005 energy bill They note that the speed at which new biofuel technologies take hold depends in part on government investment in research and market incentives An NRDC report forecasts that all ofthe US transportation needs for fuel could come from abuts by 2050 But that scenario also depends on an unlikely boost in investment11 bile lion in funding for biomass in the next six ears much of it for research to overcome the recalcitrance of processing lignocellulose into ethanol And the NRDC scenario also hinges on changes in community planning and big increases in automobile ef ciency standards the cheapest and fastest way to end our addice tion to oil says NRDC s Greene Box 5 Potential downsides Biofuels are not necessarily a boon for the environment In the United States some newer corn grain ethanol facilities are switching to the use of cheaper coal instead of cleaner burning natural gas as a power source And this March the EPA proposed allowing ethanol plants to more than doubletheir emissions a measure backed by more than 30 members of Congress Activists and policy makers in Europe are concerned that the European nations could ramp up im orts of palm oil from tropical plantations to meet ambitious biofuel targets for their large diesel fleet Although the fuel is plentiful and cheap palm oil plantations are a prime driver of forest destruction in Southeast Asia according to The World Wildlife Fund and other environmental groups Palm oil acreage increased 11 last decade in Indonesia according to Worldwatch and plans underway would convert a million more acres to new plantations Of course using domestic European oils in fuels instead also could create new markets for palm oils in foo In the United States some policy makers are calling for importing sugarcane ethanol from Brazil an option currently burdened by high tariffs Sugarcane yields about twice as much ethanol as corn grain and by most estimates has higher greenhouse gas benefits Fig 4 in part because it is easier to produce ethanol from it But many sugarcane plantations are carved from the Cerrado a biologically diverse grassy ecosystem in Brazil All that ties into how we use the acreage we have That s the 64000 question about biofuels says Farrell How much land Ways to make room for biofuel crops include rotating them with food crops using marginal acreage and gleaning biomass from conventional crops In the United States 349million acres are devoted to agriculture but 39million acres of less productive land has been set asideworldwide 250million to 25billion acres of marginal land could be used for high biomass biofuel plants according to Worldwatch A recent US government scenario says that over a billion tons of biomass could be made available within a few decadesienough for 60billion gallons of ethanol Under this scenario 60million acres would be planted with biofuel perennials like poplar and switchgrass This study is more ambitious than one by the Rocky Mountain Institute a think tank in Golden Coloradoiand more conservative than one by the N All the scenarios make assumptions about technology and agricultural changes in the future The NRDC and US government studies both factor in big increases in the yields of switchgrass and a boost in the efficiency of extracting ethanol from it And the NRDC study calls for supplanting all of today s soybean crops with switchgrass and then extracting protein for animal feed from the grass instead of soybeans a very tall order to try and supplant that with another technology Even biofuel s biggest boosters warn of the environmental impacts if biofuel technology is implemented carelessly Box Siand they caue tion against viewing biomass as a panacea for our energyproblems The thing to remember about fossil fuels is that they are the stored solar energy of eons and millennia that we are now burning over decades We haven t evenleveled off our fossil fuel use yet says Leadbetter lt s VOLUME 24 NUMBER 7 1 Talukder K Lowrlignin wood a case study Nat Biotechnol 24 3957395 2005 2 Farrell A E 913 Etnanol can contribute to energy and envirnonrnental goals Science 311 5067508 2005 3 Tilrnan D Re cn PB amp Knops J NI H Biodiversity and ecosystem stability in a decaderlong grassland experiment Natl9441 6297532 2006 JULY 2006 NATURE BIOTECHNOLOGY


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