Improved acylation of phytosterols catalyzed by Candida antarctica lipase A with superior catalytic activity

• Published in: Biochemical Engineering Journal
• Main Authors: Panpipat, Worawan, Xu, Xuebing, Guo, Zheng
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2013
• Subjects: Antarc*; Antarctica
• Online Access: https://pure.au.dk/portal/da/publications/improved-acylation-of-phytosterols-catalyzed-by-candida-antarctica-lipase-a-with-superior-catalytic-activity(e606e2a7-c78d-45bf-a71e-80c8e4255e36).html; https://doi.org/10.1016/j.bej.2012.09.017; https://pure.au.dk/ws/files/55295979/Improved_acylation_of_phytosterols_catalyzed_by_Candida_antarctica.pdf

This work reported a novel approach to synthesize phytosterol (ˇ-sitosterol as a model) fatty acid esters by employing Candida antarctica lipase A (CAL A) which shows a superior catalytic activity to other lipases. A series of ˇ-sitosteryl fatty acid esters (C2–C18) have been successfully prepared with structural identification of products by 1H NMR and Fourier transform-infrared spectroscopy (FTIR). Compared to other immobilized lipases, CAL A achieves 6–14 times faster esterification of ˇ-sitosterol with myristic acid. CAL A shows low activity toward short chain fatty acids (C2–C6), and remarkably high activity for medium and long chain ones (≥C8). Reaction time, temperature, enzyme load, substrate ratio and concentration, and solvent property are found to profoundly influence reaction rates. A pronounced correlation between enzyme activities and log P values of solvents, among the solvents with a broad spectrum of log P values, was observed. 93–98% yield of ˇ-sitosteryl esters could be achieved with hexane as solvent, fatty acid (C8–C18)/ˇ-sitosterol (1:1, mol:mol), 5–10% CAL A load at 40–50 ◦C for 24 h. This work demonstrated the promising potential of CAL A in bioprocess of phytosterols for value-added application.