Efficient water removal in lipase‐catalyzed esterifications using a low‐boiling‐point azeotrope

• Published in: Biotechnology and Bioengineering
• Main Authors: Yan, Youchun, Bornscheuer, Uwe T., Schmid, Rolf D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2002
• Subjects: Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.1002/bit.10084; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fbit.10084; https://onlinelibrary.wiley.com/doi/pdf/10.1002/bit.10084

Abstract High conversions in lipase‐catalyzed syntheses of esters from free acyl donors and an alcohol requires efficient removal of water preferentially at temperatures compatible to enzyme activity. Using a lipase B from Candida antarctica (CAL‐B)‐mediated synthesis of sugar fatty‐acid esters, we show that a mixture of ethyl methylketone (EMK) and hexane (best ratio: 4:1, vo/vo) allows efficient removal of water generated during esterification. Azeotropic distillation of the solvent mixture (composition: 26% EMK, 55% hexane, 19% water) takes place at 59°C, which closely matches the optimum temperature reported for CAL‐B. Water is then removed from the azeotrope by membrane vapor permeation. In case of glucose stearate, 93% yield was achieved after 48 h using an equimolar ratio of glucose and stearic acid. CAL‐B could be reused for seven reaction cycles, with 86% residual activity after 14 d total reaction time at 59°C. A decrease in fatty‐acid chain length as well as increasing temperatures (75°C) resulted in lower conversions. In addition, immobilization of CAL‐B on a magnetic polypropylene carrier (EP 100) facilitated separation of the biocatalyst. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 31–34, 2002; DOI 10.1002/bit.10084