Algae are a raw material of the future. Whether as an energy supplier, a component of cosmetics, or a food supplement, they have diverse uses. Novel facilities constructed by the start-up Mint Engineering now enable people to breed microalgae as food right in cities. Photobioreactors consisting of small tubes can be attached to building facades for the first time and hence save space. Unused surfaces take on a new function and the protein-rich single-cell organisms are harvested where they are needed. In restaurants, for example, they can now be served fresh in smoothies, sauces, or froth.