Growth and anthraquinone production of Morinda elliptica cell suspension cultures in a stirred-tank bioreactor

The effects of medium strategy, number of impellers, aeration mode, and mod e of operation on Morinda elliptica cell suspension cultures in a stirred-t ank bioreactor are described. A lower number of impellers and continuous ae ration contributed toward high cell growth rate, whereas a higher number of impellers reduced cell growth rate, although not anthraquinone yield. The semicontinuous mode could indirectly imitate the larger scale version of pr oduction medium strategy and improved anthraquinone production even with 0. 012% (v/v) antifoam addition. Production medium promoted both growth (maxim um dry cell weight of 24.6 g/L) and anthraquinone formation (maximum conten t of 19.5 mg/g of dry cell weight), without any necessity for antifoam addi tion. Cultures in production medium or with higher growth rate and anthraqu inone production were less acidic than cultures in growth medium or with lo wer growth rate and anthraquinone production. Using the best operating vari ables, growth of M. elliptica cells (24.6 g/L) and anthraquinone yield (0.2 5 g/L) were 45% and 140%, respectively, lower than those using a shake flas k culture after 12 days of cultivation.