Abstract: There is provided a culture bag for use in a photobioreactor. The bag can comprise at least one wall having at least one inlet disposed at a first end portion of the at least one wall or adjacently thereto. The at least one wall defines an internal chamber for receiving a culture medium. The bag also comprises at least one injector for injecting a gas inside the bag, the at least one injector being disposed at a second end portion of the at least one wall or adjacently thereto. The bag also comprises at least one outlet for harvesting a content of the bag, the at least one outlet being disposed at the second end portion of the at least one wall or adjacently thereto. The bag can be translucent or transparent and be effective for holding and sealingly maintaining the culture medium inside the bag and inside the photobioreactor. There is also provided a photobioreactor and a photobioreator modular system.