Photofuel studies and advances the biocatalytic production of alternative liquid transportation fuels, which require only sunlight, CO2 and water. Microbial cells directly excrete hydrocarbon and long chain alcohol fuel compounds to the medium from which they are separated, without the need to harvest biomass. This significantly improves the costs and energy balances as only a minimum of nutrients is required for self-replication of the biocatalyst, whilst cell harvesting, drying and lipid extraction is omitted. Such minimum-input systems are compatible with operation on degraded or desert land which avoids the pitfalls of most of the currently available biofuel technologies. The products are drop-in fuels that fully or partially replace their fossil counterparts without the need for new infrastructure. To set a benchmark for alternative solar fuels, three research groups will collaborate in the advancement of the biocatalysts from TRL 3. The best biocatalytic system(s) will be up-scaled and operated outdoors in photobioreactors modified for direct fuel separation at a scale of several cubic meters (TRL 4-5). The identification of optimal future fuel blends with a fossil fuel base and Photofuel biofuels as additives, as well as the analysis of performance and emissions in car or truck engines, will be evaluated by the oil- and automotive-industry partners. The entire pathway will be assessed for environmental and economic performance as well as social acceptance of large scale production in rural communities and by the consumer. All results will be combined to a business development plan, which clearly identifies the opportunities but also the challenges prior to an economic fuel production in compliance to the EC Fuel Quality Directive.