Ultrasound assisted production of daunorubicin: Process intensification approach

• Daunorubicin fermentation process was intensified with ultrasound irradiation.
• Higher duty cycle has detrimental effect on bacterial viability.
• Reduced glucose conc. represents enhanced cellular uptake.
• ESEM micrograph of S. peucetius indicates structural integrity after ultrasonication.

The present endeavor encompasses process intensification approach for daunorubicin fermentation from Streptomyces peucetius MTCC 4332 using ultrasonic stimulus. One factor at a time design was employed to illustrate the effect of various process parameters of ultrasonic irradiation (irradiation at various growth phases, power, irradiation time and duty cycle) on enhancement of daunorubicin productivity. Ultrasonic irradiation on 4th day of bacterial culture growth at 25 kHz frequency with 160 W power and 40% duty cycle for 5 min shows 1.62 fold increase in daunorubicin production (from 46.96 to 76.42 mg/l) as compared to non-sonicated batch fermentation. Higher duty cycle imparts detrimental effect on bacterial cell and decreases viability of cells. Environmental scanning electron microscopic analysis depicted structural integrity of bacterial cell after irradiation of optimized ultrasonic dose. Moreover, declined glucose concentration after ultrasonication from 1.16 to 0.46 mg/l after 7 days of incubation, implies that cellular uptake of substrate was increased and productivity of cell was also enhanced. Hence, proposed process intensification approach will be very useful to boost up the fermentation of various therapeutic molecules.