Ultrasound-assisted enzymatic synthesis of medium- and long-chain triacylglycerols from tricaprylin and algal oil.

Medium and long-chain triacylglycerols (MLCTs) are functional lipids, but their efficient synthesis in various systems remains challenging. An ultrasound-assisted enzymatic interesterification process was developed using tricaprylin and algal oil as substrates. The optimized enzymatic conditions were obtained by artificial neural network modeling. The structure of enzyme and computational fluid dynamics (CFD) of enzymatic process were both evaluated. The results showed that the MLCT yield reached 69.16%, with Cy-Cy-DHA as the predominant product (28.99%). Only slight structural changes were observed in the enzyme after ultrasound treatment, while the apparent reaction rate constant increased by nearly 2.8-fold and the activation energy decreased. CFD showed that ultrasound improved substrate diffusion and mixing with a lower maximum static pressure than stirring (178 vs. 259 Pa), suggesting MLCT synthesis was enhanced mainly by mass transfer intensification. This study provides valuable insights into mechanisms underlying ultrasound-enhanced enzymatic processes and guides their further scale-up and industrial application.