The influences of dissolved oxygen and shearing force on the production of extracellular polysaccharides by Polianthes tuberosa callus were evaluated independently by use of a fixed-bed reactor. Oxygen consumption rate of the callus increased with increasing dissolved oxygen (DO) concentration, while the polysaccharide productivity peaked at DO concentration of 7.6 g/m(3). When DO concentration was kept around 7.6 g/m(3), the maximized polysaccharide productivity was observed with respect to shearing force generated by the flow of medium. Assessment of culture performance in an industrially conventional vessel with aeration and agitation showed that DO concentration could be controlled around 7.6 g/m(3) under a stable operation condition of shearing force, though a desirable condition of shearing force was difficult to achieve.