2 Jul 2019

Production and Surfactant Properties of Tert-Butyl α-D-Glucopyranosides Catalyzed by Cyclodextrin Glucanotransferase

While testing the ability of cyclodextrin glucanotransferases (CGTases) to glucosylate a series of flavonoids in the presence of organic cosolvents, we found out that this enzyme was able to glycosylate a tertiary alcohol (tert-butyl alcohol). In particular, CGTases from Thermoanaerobacter sp. and Thermoanaerobacterium thermosulfurigenes EM1 gave rise to the appearance of at least two glycosylation products, which were characterized by mass spectrometry (MS) and nuclear magnetic resonance (NMR) as tert-butyl-α-D-glucoside (major product) and tert-butyl-α-D-maltoside (minor product). Using partially hydrolyzed starch as glucose donor, the yield of transglucosylation was approximately 44% (13 g/L of tert-butyl-α-D-glucoside and 4 g/L of tert-butyl-α-D-maltoside). The synthesized tert-butyl-α-D-glucoside exhibited the typical surfactant behavior (critical micellar concentration, 4.0–4.5 mM) and its properties compared well with those of the related octyl-α-D-glucoside. To the best of our knowledge, this is the first description of an enzymatic α-glucosylation of a tertiary alcohol.

Chemical structure of the synthesized glycosides: (1) tert-butyl-O-α-D-glucopyranoside and (2) tert-butyl-O-α-D-maltoside. 

Variation of surface tension vs. concentration for tert-butyl and octyl glucosides.

''Production and Surfactant Properties of Tert-Butyl α-D-Glucopyranosides Catalyzed by Cyclodextrin Glucanotransferase'' H. Garcia-Arellano, J. L. Gonzalez-Alfonso, C. Ubilla, F. Comelles, M. Alcalde, M. Bernabé, J-L Parra, A. O. Ballesteros and F. J. Plou. Catalysts  (2019), https://doi.org/10.3390/catal9070575

1 Jul 2019

INNOVA Prize to José Luis Gonzalez-Alfonso

Our PhD student José Luis Gonzalez-Alfonso has been awarded with the INNOVA Prize auspiced by the Spanish Platform SUSCHEM (Sustainable Chemistry) to the best collaborative work between public and private institutions. This work was performed in collaboration with Professor Yoshihiko Hirose (Enzyme Techno, Japan). The ceremony took place in Madrid on June 26th 2019.
The awarded work was: ''Enzymatic synthesis of a novel pterostilbene α-glucoside by the combination of cyclodextrin glucanotransferase and amyloglucosidase''. J.L. González-Alfonso, D. Rodrigo-Frutos, E. Belmonte-Reche, P. Peñalver, A. Poveda, J. Jimenez-Barbero, A.O. Ballesteros, Y. Hirose, J. Polaina, J.C. Morales, M. Fernández-Lobato and F. J. Plou. Molecules 25;23(6) (2018). doi:10.3390/molecules23061271
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