The OLIZERO project: Closing loops in olive groves and olive mills with integrated biorefineries,

International audienceThe volatility of fossil resources prices, the uncertainty of their long-term availability and the environmental, climatic and societal problems posed by their operation, lead to the imperative of the energy transition, development and use of other alternative and sustainable resources. In Europe, established feedstocks for ethanol and biodiesel have thrived largely under the protection of subsidies but first generation biofuels have triggered a debate within the European Union (EU) over their economic and environmental sustainability. Acknowledging that indirect land-use change can reduce the greenhouse gas emissions savings, the EU has reshaped its biofuel policy. It has a set of sustainability criteria to ensure that the use of biofuels guarantees real carbon savings and protects biodiversity. From a sustainability perspective, biofuels and bioliquids offer indeed both advantages (more secure energy supply, emissions reductions, reduced air pollution, production of high added-value molecules) and risks (monocultures, reduced biodiversity, and even higher emissions through land use change). Approaching economic, environmental and social sustainability at the local level and in an integrated way helps to maximize benefits and minimize risks. This approach has been adopted to assess the relevance of bio-refineries supplied from lignocellulosic biomass and implementing emerging technologies such as pyrolysis process in an olive-growing area (Sierra Mágina). Sierra Mágina is vulnerable to climate change because of its high level of specialization in olive growing and the burning in loco of pruning waste (several dozen of kilos per tree) contributes to greenhouse gases (GHG) emissions. Therefore this territory has been selected for the OLIZERO project.The OLIZERO bio-refinery concept is part of an interdisciplinary thinking which aims to optimize the use of biomass available in a specific territory by analyzing local and integrated production of finished and/or intermediate products and higher added-value molecules (from solvents to aroma, flavors and products of medical interest). The final objective is to develop innovative methods for recovering chemicals from the most difficult valuable fractions (lignocellulosic fractions). The project is then about a study of the feasibility of a bio-refinery coupled to existing olive mills. We initially identified and mapped the resource available in a Spanish territory located in Sierra Mágina, Andalucía. We have in a second step associated a Py-GCMS analysis from a sampling of several available olive tree cuttings in this territory. This preliminary study will provide a picture of what kind of chemicals can be obtained from a pyrolysis process. The second on-going step is to perform lab scale pyrolysis experiments with the selected resources. The coupling of the territorial study and physicochemical analysis will optimize the annual output of high-value molecules and associated biochar (fertilizer). It is then necessary to define the geographic data (workflow, localization, mapping etc.) to plan the availability of the biomass according to harvest periods and secondly physicochemical characteristics to assess the nature of bio-molecules that will be extracted (volumes and material flow).KEYWORDS: pruning waste, pyrolysis, Py-GCMS, biorefinery, waste reduction; low-carbon olive-growing systems, pathogenic strain, EU policy.ACKNOWLEDGEMENTIdEx Sorbonne Paris Cité and Région Ile de France are acknowledged for their financial support.Pôle image and Coumba Doucouré (Université Paris 13) are acknowledged for their technical support