A new bioreactor for paclitaxel production based on foam separation

Abstract

ABSTRACTWe report here the development of a new bioreactor (bioreactor with foam separation, BFS) for efficient production and recovery of paclitaxel that circumvents paclitaxel's inhibitory effects on growth through a feedback mechanism. The BFS captures paclitaxel through its hydrophobic interaction with the foam generated by aerated culture medium. The BFS comprises co‐axial 0.65 dm3 outer (150 mm height and 75 mm diameter) and 0.15 dm3 inner vessels (90 mm height and 50 mm diameter) equipped with a ball‐type sparger (5–10 µm pore size, 10 mm diameter) and a wire‐framed draft tube covered by a water‐permeable cellulose bag (150 × 40 mm, 100 µm maximum pore size). The BFS was tested by adding paclitaxel alone to the medium of 0.12 dm3 in the inner vessel and collecting it in the foam that overflowed into the outer vessel. Paclitaxel was separated with first‐order kinetics and was optimally recovered using an aeration rate of 0.05 dm3 min−1 (0.21 vvm). Next, a Taxus cuspidata callus was cultured using the optimal aeration rate. A conventional shaking culture (110 rpm) served as the control using a 0.2 dm3 Erlenmeyer flask (0.12 dm3 medium). Paclitaxel was maintained at less than 0.02 g m−3 in the inner vessel of the BFS. Consequently, there was no feedback inhibition, and the paclitaxel production increased by a factor of five in the BFS compared with the control culture where there was feedback inhibition by the high concentration of paclitaxel. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.