ii. Effect of agitation speed on cell survival and viability

Speed of agitation directly affected the growth and viability of cells in suspension cultures due to aeration and shearing effect. The maximum fresh weight and maximum viability (Figure 11.6 B) was observed at 120 rpm. At lower agitation (60 rpm), the cells died due to aggregation and clumping; only the cells at the outermost layer of the aggregate were alive and fluorescent green when stained with fluorescein diacetate (FDA) (Figure 11.6 A). At higher speed (240 rpm), the cells died due to rupturing (Figure 11.6 C).

 

Figure 11.6: Cells stained with 1% fluorescein diacetate solution . A. cellular clump at 60 rpm, showing unstained dead cells in the centre of cell aggregate and live cells fluoresce green at the periphery , B. The cultures maintained at 120 rpm in the cell suspension, showing aggregates of live and healthy, fluorescent green stained cells , C. Same at 240 rpm, showing dead clumps (dark bodies) and sheared cells.