Oxygen-balanced mixotrophy (OBM) is a particular type of microalgae mixotrophic cultivation, where the supply of an organic carbon substrate is adjusted to match heterotrophic oxygen consumption with photosynthetic production. In this way, the need for aeration is eliminated due to intracellular gas recycling during daytime. After implementing this process at lab scale, we sought to explore its scalability in a tubular photobioreactor (TPBR). In this study, OBM was implemented in a two-phase tubular photobioreactor of 1700 L placed in a greenhouse and exposed to sunlight. The process was run with the polyextremophilic species