News and Trends

The development of "tailored" bioenergy crops is one research area where crop biotechnology can contribute to lowering the cost of cellulose-ethanol production from lignocellulosic biomass. "Tailored" lignocellulosic plant biomass feedstocks with low lignin content could improve cell-wall digestibility and reduce the costs of pretreatment. (Pretreatment is a thermochemical process where chemical agents (in combination with heat) wrench-off the tight lignin wrapping of the plant biomass and expose the cellulose/hemicellulose fibers for further processing to ethanol). Researchers from Purdue University (United States) report that modifying the lignin composition in a model plant, Arabidopsis thaliana, can improve cell-wall digestibility and makes pretreatment more efficient. Lignin is a phenolic polymer containing p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) units as building blocks. By modifying the relative abundance of the G-units and S-units in mutant and genetically-modified model plant lines, they showed that pretreatment performance (by liquid hot water addition) was improved. They concluded that "increasing lignin S monomer content through genetic engineering may be a promising approach to increase the efficiency and reduce the cost of biomass to biofuel conversion". The full results are published in the open-access journal, Biotechnology for Biofuels.

The European Commission (EC) recently released its sequel publication on the biosafety issues related to the use and applications of genetically modified organisms (GMO) in the European Union (EU). The EU has been known to take a precautionary approach on new technologies (such as GMO technology), and it has often stressed the need to identify and quantify potential risks and benefits. The publication titled, "A Decade of EU-funded GMO Research", reviews the last ten years of research projects launched under the Framework Programmes for research, focusing on safety aspects of GMO's, and also taking account of developments in the field over time. Fifty research projects were assessed and classified into five areas: (1) Environmental Impacts of GMO's, (2) GMO's and Food Safety, (3) GMO's for biomaterials and biofuels –emerging technologies, (3) Risk assessment and management –policy support and communication. The results, as highlighted by the bioenergy website, indicate that "there is no scientific evidence associating GMOs with higher risks for the environment or for food and feed safety than conventional plants and organisms". The present research projects are said to be more "carefully integrated and look at the potential technological benefits as well as the risks". A biofuels-related project on the development of "new strategies for breeding added-value plants with modified cell-wall properties" that are better suited for processing of second-generation (lignocellulosic) bioenergy feedstocks is described. Leading scientists have been brought together to work on strategies for plant wall deconstruction. Year 1 accomplishments include the development of a high-throughput robotic system "to identify plants with altered digestibility in large populations of plants, and a reactor system for the more detailed analysis of plants with altered digestibility". The full EU report can be accessed at the Europa website (URL above).

Energy Crops and Feedstocks for Biofuels Production

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Researchers from the Coastal Plains Soil, Water, and Plant Research Center of the United States Department of Agriculture, Agricultural Research Service (USDA-ARS) assessed the use of two summer legumes as potential bioenergy crops. Keeping in mind that good bioenergy crops should have high dry matter/energy yields and reduced agricultural inputs, they considered the growing of legumes as biofuel feedstocks during the late summer season in the Southeastern region in the United States. Legumes have high biomass yields with no nitrogen fertilizer requirements, and planting these potential feedstocks during fallow periods could have many of the environmental benefits. The researchers assessed sunn hemp (Crotolaria juncea) and cowpeas (Vigna unguiculata) in terms of biomass yield, energy content/yield, plant mineral concentrations; and pyrolytic degradation characteristics. Results showed that sunn hemp had higher biomass and energy yields compared to cowpea. The energy content in sunn hemp was also 6% higher than cowpea. Sunn hemp was also found to have lower plant mineral concentrations (K, Ca, Mg, S) that are known to reduce thermochemical conversion efficiencies of biomass-to-biofuel conversion processes. The full paper is published in the journal, Biomass and Bioenergy (URL above).

Biofuels Processing

The Energy Biosciences Institute (EBI) at the University of California, Berkeley (United States) recently released a report on "A Realistic Technology and Engineering Assessment of Algae Biofuel Production". The report assesses microalgae-biofuel production economics based on five (existing or expected near-term) technology scenarios. The scenarios include (1) microalgal cultivation, (2) algal harvesting by bioflocculation, and (3) algal oil extraction by hexane. The algal biofuel production technology usually involves the mass cultivation of the algae, followed by algal harvesting and oil extraction, and finally, the conversion of the extracted oil to biodiesel by a chemical reaction with methanol (known as "transesterification"). Highlights of the report include the following: (1) development of cost-competitive algae biofuel production will require much more long-term research, development and demonstration; even with low capital charges, it is not possible to produce microalgal biofuels cost competitively with fossil fuels without major advances in technology, (2) the major cost improvement would be in the biology; that is, the development of algal strains (that can be reliably grown and harvested in outdoor ponds) with at least double the biomass and oil productivity through strain selection and genetic modification. The full report can be accessed at the website of the Energy Biosciences Institute (URL above).

Biofuels Policy and Economics
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The effects of biofuel policies and associated interactions with other policies (i.e., environmental, energy and agricultural policies) were analyzed by economic cost-benefit methods by Harry de Gorter and David R. Just of Cornell University (United States). Their paper is published in the journal, Applied Economics Perspectives and Policy (URL above). Biofuel policies are often motivated by concerns related to energy security, environmental protection and agricultural development, and these interactions (from an economic point of view) can be "complex". One reason cited was "the intricate interrelationships between energy and commodity markets and the varied environmental consequences". In their analysis, they attempted to "disentangle the key interactions in this [complex] system of policy instruments by analyzing each biofuel policy on its own merits, in relation to each other, as well as to other environmental, energy and agricultural policies". One of the findings of the analysis shows that "regulations that mandate an increase in the amount of biofuels incorporated into current energy supplies are superior to all other policies; [but] as soon as policies are combined, there can be negative economic interactions". As an example, if the biofuel-consumption mandate is added with a biofuel subsidy, the combined policies would result in failure to increase ethanol consumption and would instead subsidize oil consumption. The study recommends for a more effective policy that would rely on "specific taxes and subsidies targeted directly at achieving specific environmental, energy and agricultural policy goals".

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Researchers from the Swedish Environmental Research Institute, the SP Technical Research Institute of Sweden (Energy Technology), and Örebro University (Sweden) report the use of the "Choice Experiment Approach" to assess Swedish farmers' values with regard to growing bioenergy crops. Choice modeling (related information below) reportedly "attempts to model the decision process of an individual or segment in a particular context", and it is also used to "estimate non-market environmental benefits and costs". In the first choice experiment (CE), the farmers were asked for their preference of two bioenergy crops and six of associated characteristics of the bioenergy crop. In a second CE, the farmers were asked how many hectares they would be be willing to grow the bioenergy crops in two scenarios: (1) on arable land with an energy crop subsidy, and (2) on set-aside land without energy crop subsidy. Some highlights of the results are: (1) for Swedish farmers who choose to grow bioenergy crops, "the choice is based on those crops that maximize their utility", and the size of the utility is said to depend on both net income and the crop's cultivation characteristics, (2) willow was seen to be the bioenergy crop with the highest potential, but requires specialized machinery for planting/harvesting, and has a long rotation period (20 years), (3) "Farm characteristics such as leased land, rented land, share of set-aside land, and type of farming had an insignificant effect on the willingness to grow energy crops". The full results are published in the Biomass and Bioenergy journal (URL above).

Related information on the choice experiment method: