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Box 2: Biotechnology applications for biofuelsMany existing biotechnologies can be applied to improve bioenergy production, for example, in developing better biomass feedstocks and improving the efficiency of converting the biomass to biofuels. Biotechnologies for first-generation biofuels The plant varieties currently used for first- generation biofuel production have been selected for agronomic traits relevant for food and/or feed production and not for characteristics that favour their use as feedstocks for biofuel production. Biotechnology can help to speed up the selection of varieties that are more suited to biofuel production – with increased biomass per hectare, increased content of oils (biodiesel crops) or fermentable sugars (ethanol crops), or improved processing characteristics that facilitate their conversion to biofuels. The field of genomics – the study of all the genetic material of an organism (its genome) – is likely to play an increasingly important role. Genome sequences of several first- generation feedstocks, such as maize, sorghum and soybean, are in the pipeline or have already been published. Apart from genomics, other biotechnologies that can be applied include marker-assisted selection and genetic modification. Fermentation of sugars is central to the production of ethanol from biomass. However, the most commonly used industrial fermentation micro-organism, the yeast Saccharomyces cerevisiae, cannot directly ferment starchy material, such as maize starch. The biomass must first be broken down (hydrolysed) to fermentable sugars using enzymes called amylases. Many of the current commercially available enzymes, including amylases, are produced using genetically modified micro-organisms. Research continues on developing efficient genetic yeast strains that can produce the amylases themselves, so that the hydrolysis and fermentation steps can be combined. Application of biotechnologies for second-generation biofuels Lignocellulosic biomass consists mainly of lignin and the polysaccharides cellulose (consisting of hexose sugars) and hemicellulose (containing a mix of hexose and pentose sugars). Compared with the production of ethanol from first-generation feedstocks, the use of lignocellulosic biomass is more complicated because the polysaccharides are more stable and the pentose sugars are not readily fermentable by Saccharomyces cerevisiae. In order to convert lignocellulosic biomass to biofuels the polysaccharides must first be hydrolysed, or broken down, into simple sugars using either acid or enzymes. Several biotechnology-based approaches are being used to overcome such problems, including the development of strains of Saccharomyces cerevisiae that can ferment pentose sugars, the use of alternative yeast species that naturally ferment pentose sugars, and the engineering of enzymes that are able to break down cellulose and hemicellulose into simple sugars. Apart from agricultural, forestry and other by-products, the main source of lignocellulosic biomass for second- generation biofuels is likely to be from “dedicated biomass feedstocks”, such as certain perennial grass and forest tree species. Genomics, genetic modification and other biotechnologies are all being investigated as tools to produce plants with desirable characteristics for second- generation biofuel production, for example plants that produce less lignin (a compound that cannot be fermented into liquid biofuel), that produce enzymes themselves for cellulose and/or lignin degradation, or that produce increased cellulose or overall biomass yields. Sources: based on FAO, 2007a The Role of Agricultural Biotechnologies for Production
of Bioenergy in Developing Countries. Seminar, 12 October 2007, Rome, Italy. Organized
by the FAO Working Group on Biotechnology and the FAO Working Group on Bioenergy. Rome
(seminar papers available at
www.fao.org/biotech/seminaroct2007.htm Source: FAO, The State of Food and Agriculture, Biofuels: Prospects, Risks and Opportunities (2008) Related publication:
Other Figures & Tables on this publication: TABLE 1: Biofuel production by country, 2007 TABLE 2: Biofuel yields for different feedstocks and countries TABLE 3: Hypothetical potential for ethanol from principal cereal and sugar crops TABLE 4: Voluntary and mandatory bioenergy targets for transport fuels in G8+5 countries TABLE 5: Applied tariffs on ethanol in selected countries TABLE 6: Total support estimates for biofuels in selected OECD economies in 2006 TABLE 8: Energy demand by source and sector: reference scenario TABLE 9: Land requirements for biofuel production TABLE 10: Water requirements for biofuel crops TABLE 13: Share of net staple food-seller households among urban, rural and total households Box 1: Other types of biomass for heat, power and transport Box 2: Biotechnology applications for biofuels Box 3: Biofuel policies in Brazil Box 4: Biofuel policies in the United States of America Box 5: Biofuel policies in the European Union Box 6: Main sources of uncertainty for biofuel projections Box 7: Biofuels and the World Trade Organization Box 8: Biofuels and preferential trade initiatives Box 9: The Global Bioenergy Partnership Box 10: Biofuels and the United Nations Framework Convention on Climate Change Box 11: Jatropha – a “miracle” crop? Box 12: Agricultural growth and poverty reduction Box 14: Biofuel crops and the land issue in the United Republic of Tanzania Figure 1: World primary energy demand by source, 2005 Figure 2: Total primary energy demand by source and region, 2005 Figure 3: Trends in consumption of transport biofuels Figure 4: Biofuels – from feedstock to end use Figure 5: Uses of biomass for energy Figure 6: Conversion of agricultural feedstocks into liquid biofuels Figure 7: Estimated ranges of fossil energy balances of selected fuel types Figure 8: Support provided at different points in the biofuel supply chain Figure 9: Biofuel production costs in selected countries, 2004 and 2007 Figure 10: Breakeven prices for crude oil and selected feedstocks in 2005 Figure 11: Breakeven prices for maize and crude oil in the United States of America Figure 12: Breakeven prices for maize and crude oil with and without subsidies Figure 13: Maize and crude oil breakeven prices and observed prices, 2003–08 Figure 14: Price relationships between crude oil and other biofuel feedstocks, 2003-08 Figure 15: Food commodity price trends 1971–2007, with projections to 2017 Figure 16: Global ethanol production, trade and prices, with projections to 2017 Figure 17: Major ethanol producers, with projections to 2017 Figure 18: Global biodiesel production, trade and prices, with projections to 2017 Figure 19: Major biodiesel producers, with projections to 2017 Figure 20: Total impact of removing trade-distorting biofuel policies for ethanol, 2013–17 average Figure 21: Total impact of removing trade-distorting biofuel policies for biodiesel, 2013–17 average Figure 22: Life-cycle analysis for greenhouse gas balances Figure 23: Reductions in greenhouse gas emissions of selected biofuels relative to fossil fuels Figure 24: Potential for cropland expansion Figure 25: Potential for yield increase for selected biofuel feedstock crops Figure 26: Potential for irrigated area expansion Figure 27: Agricultural trade balance of least-developed countries Figure 28: Distribution of poor net buyers and sellers of staple foods1 |
