Growth of plant cell cultures is demonstrated in an uncontrolled, simple, and inexpensive plastic-lined vessel. Sustained specific growth rates of 0.22 day(-1) for Hyoscyamus muticus cell suspension cultures are achieved in a low-cost gas-sparged bioreactor configuration (6.5 L working volume, wv) which is comparable to an "optimized" 5 L wv mechanically agitated fermenter. In an effort to reduce bioreactor costs, the need for an autoclavable vessel was eliminated. Sterilization is achieved by separate autoclaving of the plastic,liner and by gas-phase sterilization using ethylene oxide. The initial,run sterilized with ethylene oxide displayed a long lag, apparently due to residual sterilant gas. Because ethylene oxide could eliminate costs associated with autoclave rated vessels, a quantitative basis for aeration time was developed by experimental measurements and modeling of diffusion in the polymer liner. Operational techniques to eliminate toxicity are implemented to grow 0.2 kg dry weight of plant cells in 13 days in a 40 L (28.5 L wv) air-lift bioreactor without autoclave sterilization. The biomass yields for all reactors were statistically indistinguishable from shake flask culture.