Effect of air stone pore size and gas flow rate on the recovery efficiency of paclitaxel from biomass in gas bubble-assisted extraction

The effect of air stone pore size and gas flow rate on the extraction efficiency of gas bubble-assisted extraction to recover paclitaxel derived from Taxus chinensis was investigated. The yield of paclitaxel at air stone pore sizes of 10, 30, and 43 µm was 68, 82, and 83% at a gas flow rate of 1.0 L/min, 81, 82, and 85% at a gas flow rate of 1.5 L/min, and 83, 83, and 85% at a gas flow rate of 2.0 L/min, respectively. As the air stone pore size and gas flow rate increased, the yield increased and was significantly improved compared to the 59% yield in the conventional extraction. In addition, as the air stone pore size and gas flow rate increased, the extraction rate constants increased to 1.2302–3.6740 mL/mg·min (10–43 µm, 1.0 L/min), 3.2212–3.9247 mL/mg·min (10–43 µm, 1.5 L/min), and 3.7219–3.9678 mL/mg·min (10–43 µm, 2.0 L/min). The effective diffusion coefficients increased to 3.33928×10 −11 −4.16299×10 −11 m 2 /s (10–43 µm, 1.0L/min), 3.93771×10 −11 −4.71392×10 −11 m 2 /s (10–43 µm, 1.5 L/min), and 4.68557×10 −11 −4.84878×10 −11 m 2 /s (10–43 µm, 2.0 L/min). While the mass transfer coefficients increased to 3.05840×10 −5 −3.71015×10 −5 m/s (10–43 µm, 1.0 L/min), 3.53749×10 −5 −4.13443×10 −5 m/s (10–43 µm, 1.5 L/min), and 4.11263×10 −5 −4.23815×10 −5 m/s (10–43 µm, 2.0 L/min). A morphological analysis by SEM showed that the bubbles themselves affected cell disruption, and as the air stone pore size and gas flow rate increased, cell disruption accelerated and the recovery efficiency of paclitaxel improved.