The BIORARE project aims at evaluating the potential of BioElectrochemical Systems (BES) to become a cornerstone technology for future environmental biorefineries.

Principle of a bioelectrochemical system (BES) applied to waste biorefinery

Bulk chemicals and liquid fuels are currently produced almost exclusively from petrochemical feedstock. In the light of emission reduction targets, production of the same or functionally equivalent chemicals from renewable resources (“bio-based chemicals“) may play an important role in decreasing our environmental impact and reducing our dependence on non-renewable fossil resources. The sustainability of these bioproducts is however substantially determined by the choice of the feedstock, which may have strong implications for food production as well as for the eventual reduction of greenhouse gas emissions. In this context, using organic waste for bio‑based chemical production represents an attractive option because of high potential for fossil fuel displacement and low (even negative) feedstock costs. Thermal conversion being mainly applicable to low moisture waste, biological conversion of organic waste essentially consist of anaerobic digestion, which is today an established technology for methane production, whereas conversion of organic waste to other bio‑based chemicals is only in the exploratory research phase. Organic waste is indeed a complex, heterogeneous, and temporally variable matrix and such features severely limit its valorisation potential.

However, this situation may change. The BIORARE project relies on a new and potentially disruptive technology: microbial electrosynthesis. It has indeed been shown that it is possible to directly power microbial activity with electricity in order to catalyze microbial reductions leading to the synthesis of organic molecules. This opens the door to one of the most exciting technological application: the direct production of fuel and chemicals from renewable electricity and CO2. We believe that microbial electrosynthesis represents the most promising technology for the biorefinery of organic waste because of the following decisive advantages:

  • the oxidation of contaminated waste streams can be physically separated from the synthesis of biobased‑chemicals, rendering the recovery of the bio‑based chemical realistic,
  • microbial electrosynthesis offers the possibility to control and to regulate the cathode potential, which is linked to the Gibb’s free energy of the reaction to catalyze, offering new opportunities to steer the microbial metabolic processes.

Technologically, the working hypothesis of the BIORARE project is based on the implementation of a bioelectrochemical system (BES) for microbial electrosynthesis coupled to existing solid waste anaerobic digestion plants.