Biofuels are alternatives to fossil fuels, derived from plants and consisting mainly of bioethanol and biodiesel. Bioethanol, today the main substitute of petrol, results from the fermentation of plant sugars (starch or cellulose) while biodiesel (or bioesters) are produced from oil crops such as rapeseed, palm or soybean. Worldwide energy consumption is expected to grow by 50% by 2025, much of this mushrooming demand being driven by developing countries, while the US is still the world’s biggest polluter. The European Union has a target of having 6% of biomass-derived fuels in its total fuel consumption by 2010. This target needs strong political commitments and economical incentives, as well as multi-displinary efforts to make such a scenario technically feasible. 

Plant biotechnology is expected – and in fact needed – to embark on this project by developing high-yielding energy crops, allowing the cost-efficient transformation of their biomass into biofuels. High crop yields can be obtained by optimizing plant architecture (optimal light capture), by extending the lifespan of the light-capturing leaves, by controlling development (delayed or suppressed flowering which is a highly energy-consuming process), by avoiding biomass losses due to pathogen attacks and post-harvest diseases. The energy crops should also have suitable compositional properties (sugar and oil contents) and the chemical substrates they provide should be readily accessible for their industrial processing (easy fractionation of lignin and cellulose for instance). At each of these levels, gene transfer technologies may prove very powerful, together with other available breeding methods. The selection of novel, annual or perennial crops specially dedicated to the supply of renewable energy, will need rapid gene identification and recombination strategies using biotechnological methods.

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