Fig. 4: Lipase-catalyzed GTB hydrolysis in a column reactor packed with three-tiered colloidosomes.

a Scheme showing the continuous influx of lipase substrates (i.e., GTB) into the three-tiered colloidosomal microreactors in a column containing mobile oil phase, where the ester hydrolysis took place on the catalytic layer to generate the product efflux (i.e., glycerol and butyric acid). b 3D-reconstructed image of the three-tiered colloidosomes with RhITC-lipase catalytic layer (red fluorescence) and the substrate-enriched lumen (NBD-PE here as example, green fluorescence). Grid width: 4 μm. c, d Time-dependent conversion for GTB (0.5 M in isooctanol) hydrolysis in the colloidosome-based flow reaction, loaded lipase: 0.84 mg (c); colloidosome- and lipase-based bath reactions, loaded lipase: 0.21 mg (d). A comparison revealed the high efficiency and stability of the flow system. The concentration of GTB was calibrated according to the constructed calibration plots and corresponding equations (Supplementary Fig. 23). e Specific activity (SA) values of lipase in the colloidosome-based flow reaction at steady state (1 mL h⁻¹), and colloidosome- and lipase-based bath reactions within 20 h, respectively. f Comparison of the Michaelis–Menten kinetic parameters, k_m, v_max and k_cat, k_cat/k_m, for the colloidosome-based flow reaction, and colloidosome- and lipase-based bath reactions, respectively. Error bars indicate the SD of three replicating measurements. g SA plot of lipase in the colloidosome-based flow reaction against flow rate (substrate concentration of 0.3 M), showing the larger SA resulted from the higher flow rate of the oil mobile phase. The column temperature for all experiments in the flow system was set as 40 °C. The flow rate for all flow reactions was 1 mL h⁻¹, except for g.