A circular economy, in which waste is minimised and resources are kept within the system, relies upon inventive ways of turning waste into a resource. A new study explored the possibility of using the microalga Scenedesmus obliquus to refine and process brewery wastewater. The alga efficiently removed pollutants from the effluent, produced biomass and biofuels in a range of different forms — and with different bioactive compounds — and encouraged waste barley and wheat to germinate at increased rates. This is especially important for breweries, as barley seeds are one of the main feedstocks for the industry — and thus are key to increasing its sustainability and circularity.