Strategies to overcome foaming and wall-growth during the cultivation of Morinda elliptica cell suspension culture in a stirred-tank bioreactor

Strategies to overcome foaming and wall-growth during the cultivation of Mo rinda elliptica (Rubiaceae) cell suspension cultures in a stirred-tank bior eactor are described. Of all the strategies applied, only bubble-free aerat ion was successful in eliminating foaming by 100%. Despite the foaming effe ct of around 40% in G medium strategy with 0.012% (v/v) antifoam, the maxim um dry cell weight attained (19.2 g l(-)1) and anthraquinone (AQ) content ( 4.0 mg g(-1) DW) was nearly three times higher than that achieved in cultiv ation using 0.025% (v/v) antifoam. For continuous cell growth, the effect o f inoculum age should also be considered when anti-foam is to be added. P m edium strategy, without antifoam addition, not only promoted both growth (1 8 g l(-1)) and AQ production (9.8 mg g(-1) DW), but also resulted in lower foaming and wall-growth (below 30% level), and higher foaming reduction (30 -40%).