are hydraulically-driven bioreactors for root cell cultures (see plant cell cultures). Their key feature is a disposable bag (single-use or multi-use) in which the roots are immobilized and aerated on a frame. A two-component jet or an ultrasonic atomizer befogs the culture medium which gets distributed around the supporting frame 15, 55. The largest disposable mist-bioreactors are currently the 60 liter systems produced by former ROOTec. See bioreactors.