Assessment of the energy production potential from phytoremediation derived biomass

There are over 100 million ha of contaminated land around the world, with heavy metal (HM) contamination of particular concern. Phytoremediation, a bio-based technology, is an attractive and low-cost alternative for soil re-qualification. Although the destination of harvested biomass is commonly an obstacle to its application, this biomass can represent an opportunity for the production of energy resources. However, although it has been theoretically proposed as an excellent option, the information available in the literature on practical applications is very scarce, despite the considerable degree of success in those reported. The use of biomass cultivated in degraded soils, not involving agricultural soils for cultivation of energy crops, increases the sustainability of the use of biomass for energy generation, allowing to increase the available agricultural area while promoting the gradual decontamination of these abandoned soils. To establish this connection between soil remediation and energy production, it is necessary to select crops not only for their energy value, but also to balance it with their ability to grow under stress. Developed work points to species such as corn and sunflower, with value not only for the production of biofuels, but also potential for phytoremediation. The objective of this proposal is to maximize the tolerance of these crops in phytoremediation scenarios of HM contaminated soils through their association with mycorrhizal fungi and bacteria, promoting their yield and growth for energy valorization, taking advantage of the wide experience of the research team in the application of tools biotechnology for soil remediation and biofuel generation. This proposal provides for an innovative integrated strategy, which makes use of all parts of the plant for the generation of various energy products, maximizing the gains of remediation of contaminated soils. Combinations of the selected plants and growth promoting microorganisms will be evaluated and the soil and plant conditions will be monitored to understand the effects of the application of the tested treatments on the productivity of the crops and their remediation capacity. The cultivated plants will be used for optimization of oil extraction and fermentation to bioethanol - to be used to optimize biodiesel production. The effluents from these processes will also be used for conversion to biogas by anaerobic digestion. An important objective of this proposal is also to determine the quality of the products obtained and to understand the effect on soil contamination. Finally, an analysis of economic, social and environmental sustainability, with the identification of the steps with the most impact on final products will be executed. With these steps it will be possible to evaluate the potential contribution of this biomass derived from phytoremediation of contaminated soils as an alternative to complement the energy production.