Mixotrophy combines autotrophic and heterotrophic production of microalgae. In this way, the by-product of one process serves as the resource for the other one. Thanks to experiments on Chlorella sorokiniana and Galdieria sulphurariain close photobioreactor, Dr Abiusi discovered that in mixotrophy dosing the addition of sugar is possible to operate the bioreactor without ventilation. Instead of sugar, also waste streams from the food industry could be used, increasing the sustainability of algae production.