Photo2Fuel has contributed to the development of an innovative technology to convert CO2 by means of microorganisms into useful fuels and chemicals, specifically acetic acid and methane.
At its conclusion, the project successfully developed, tested, and coupled several photosensitizer types with specific microbial strains to harness solar energy. This biohybrid approach targeted the production of acetic acid (using Moorella thermoacetica) and methane (using Methanosarcina barkeri). The best candidate demonstrating the highest potential for upscaling to higher is the combination of the Moorella thermoacetica bacterium with a specific set of organic photosensitizers.
The initiative has also modelled the process of the acetic acid biohybrid system in two different bioreactors set ups (batch and continuous), based on experimental and literature data, with the intention to optimise it and aid the further development of the technology. Overall, there is room for improvement recommended by the modellisation and simulations made at experimental scale, adjusting parameters such as the volume of the reactor, the concentration of microorganisms, the concentration of cysteine (sacrificial electron donor), etc.
The separation process of the acetic acid has been conducted testing three different methods, and their efficiency as costs are being compared and analysed. The most efficient technique is the ion-exchange resins, although the amount of produced acetic acid should be increase in further optimisations of the process for the separation step to be economically viable.
The project concluded with a comprehensive sustainability assessment of the acetic acid biohybrid system, benchmarking its environmental, social, and economic impacts against conventional and BAU technologies. The sustainability simulations revealed that the system currently underperforms relative to the BAU baseline. This finding mirrors the conclusions from the project’s modelling tasks, underscoring the critical necessity that the Photo2Fuel process must undergo significant experimental enhancement and optimization to evolve into a technology that is environmentally sound, socially sustainable, and economically efficient.
