"Biomethanation of syngas by enriched mixed anaerobic consortium in pressurized agitated column".

In a circular economy approach, heterogeneous wastes can be upgraded to energy in the form of syngas via pyrogasification, and then to methane via biomethanation. Working at high pressure is a promising approach to intensify the process and to reduce gas-liquid transfer limitations. However, raising the pressure could lead to reaching the CO inhibition threshold of the microorganisms involved in syngas-biomethanation. To investigate the impact on pressure on the process, a 10L continuous stirred tank reactor working at 4 bars and 55 °C was implemented. Syngas (40% CO, 40% H ₂ , 20% CO ₂ ) biomethanation was performed successfully and methane productivity as high as 6.8 mmol _CH4 /L _reactor /h with almost full conversion of CO (97%) and H ₂ (98%) was achieved. CO inhibition was investigated and carboxydotrophs appeared less resistant to high CO exposition than methanogens.
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