The effect of agitation and aeration on production of cyclosporin A in batch cultures of Tolypocladium inflatum MTCC 557

The present study reports the effects of aeration and agitation on growth and production of the cyclosporin A (CyA) in batch fermentor cultures of Tolypocladium inflatum MTCC 557. Dissolved oxygen concentration, pH, dry cell wt, CyA titer and sugar utilization were continuously measured and determined. In the first step, the effect of agitation was evaluated by changing the agitation speed in the range of 250 to 450 rpm at 1 vvm. Further, after selecting the optimum agitation speed, the aeration rate was varied between 0.5 vvm to 1.0 vvm. Efficiency of aeration and agitation was evaluated through oxygen mass transfer coefficient (kLa). Maximum CyA production of 1274 mg/L with specific productivity of 0.152 mg/g.h was obtained at 350 rpm agitation and 0.75 vvm aeration. The kLa of the fermentation system supporting maximum production (350 rpm, 0.75 vvm) was 0.113 h. The oxygen transfer rate (OTR), oxygen utilization rate (OUR), and specific oxygen uptake rates (qO2) in the fermentation broth were also determined.