To reduce dependency on fossil fuels and to contribute to growing efforts to decarbonise the transport sector, biofuels provide a way to shift to low-carbon, non-petroleum fuels, with minimal changes to vehicle stock and distribution infrastructure. Whilst improving vehicle efficiency is a key cost-effective way of reducing CO2 emissions in the transport sector, biofuels will play a significant role in replacing liquid fossil fuels (particularly for those modes of transport which cannot be electrified). Production and use of biofuels can provide benefits such as increased energy security, reducing dependency on oil imports and reducing oil price volatility. Biofuels can also support economic development through creating new sources of income. BAC-TO-FUEL will respond to the global challenge of finding new sustainable alternatives to fossil fuels by developing, integrating and validating a disruptive prototype system at TRL5 which is able to transform CO2/H2 into added-value products in a sustainable and cost-effective way which: 1) mimics the photosynthetic process of plants using novel inorganic photocatalysts which are capable of producing hydrogen in a renewable way from photocatalytic splitting of water in the presence of sunlight 2) uses enhanced bacterial media to convert CO2 and the renewable hydrogen into biofuels (i.e. ethanol and butanol both important fuels for transport) using a novel electro-biocatalytic cell which can handle fluctuations in hydrogen and power supply lending itself to coupling to renewable energy technologies BAC-TO-FUEL is a multidisciplinary project which brings together leaders in the fields of materials chemistry, computational chemistry, chemical engineering, microbiology and bacterial engineering. BAC-TO-FUEL will validate a prototype system at TRL5 which is able to transform CO2/H2 into added-value products in a sustainable and cost-effective way specifically for the European transport sector.