Modulating biocatalytic activity towards sterically bulky substrates in CO2-expanded bio-based liquids by tuning physicochemical properties

• Published in: ACS Sustainable Chemistry & Engineering
• Main Authors: Hoang, Hai Nam, Granero-Fernandez, Emanuel, Yamada, Shinjiro, Mori, Shuichi, Kagechika, Hiroyuki, Medina-Gonzalez, Yaocihuatl, Matsuda, Tomoko
• Other Authors: Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - INPT (FRANCE), Université Toulouse III - Paul Sabatier - UPS (FRANCE), Tokyo Medical and Dental University - TMDU (JAPAN), Tokyo Institute of Technology - Tokyo Tech (JAPAN)
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Chemical Society 2017
• Subjects: Chimie organique; Biochimie; Génie des procédés; Pressurized carbon dioxide; Candida antarctica lipase B; 2-Methyltetrahydrofuran; Transesterification; Kinetic resolution; Substrate specificity; Solvatochromism; Green solvent engineering; Antarc*; Antarctica
• Online Access: http://oatao.univ-toulouse.fr/18596/; http://oatao.univ-toulouse.fr/18596/1/Hoang_18596.pdf; https://doi.org/10.1021/acssuschemeng.7b03018

The study of CO2-expanded liquids using a green component such as a bio-based solvent has been recently raised as a new concept for an alternative solvent, and yet been largely unexplored in literature for neither fundamental nor application studies. On the other hand, structural bulkiness of substrates remains one of the main limitations to promote enzymes as an efficient versatile catalytic tool for organic synthesis, especially biocatalysis in non-conventional solvents. Herein, we report a detailed investigation of CO2-expanded bio-based liquids as reaction media for improved biocatalysis of sterically hindered compounds. We have found that CO2 acts as a crucial trigger for various lipases to catalyse transesterification of challenging bulky alcohols in CO2-expanded 2-methyltetrahydrofuran (MeTHF). Furthermore, this study determines physicochemical and transport properties of CO2-expanded MeTHF for the first time, which were then utilized for modulating biocatalytic activity. It was found that lipase activity increased with the accordingly decrease of the dipolarity of CO2-expanded MeTHF, which is tunable by altering the concentration of CO2 in the solvent system.