Enzymatic synthesis of α‐butylglucoside lactate: A new α‐hydroxy acid derivative

Abstract

An α‐hydroxy acid derivative, α‐butylglucoside lactate, was successfully prepared by enzymatic transesterification of α‐butylglucoside with a lactate alkyl ester in a non‐aqueous medium using immobilized lipase as biocatalyst. Ester synthesis in organic solvent was optimized. Solvent choice was made on the basis of substrate solubility and enzyme stability in the medium. A solvent‐free reaction using butyllactate as lactate donor led to the highest yields. In the presence of 0.5M αbutylglucoside and 100 g/L Novozym®, a 67 % yield could be obtained within 40 h at 50°C. However, the presence of butanol by‐product limited the reaction to a maximum that could not be exceeded in closed systems. The elimination of the alcohol under reduced pressure resulted in the complete equilibrium shift of the transesterification reaction in favor of synthesis; below 15 mbars, more than 95% of 0.5M α‐butylglucoside could be converted within 30 h. Moreover, simultaneous evaporation of water allowed hydrolysis of butyllactate to be eliminated. Consequently, a very high α‐butylglucoside lactate concentration (170 g/) could be obtained in a single batch reaction. A single purification procedure, consisting of butyllactate extraction with hexane, enabled the product to be obtained at a purity above 95% (w/w). 1H and 13C NMR analysis later demonstrated that lactic acid was exclusively grafted onto the primary hydroxyl group of αbutylglucoside. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 62: 225–234, 1999.

Lipase-Catalyzed Transformations for the Synthesis of Butyl Lactate: A Comparison between Esterification and Transesterification

“…Particular attention has been devoted to the solvent‐free reacting systems specifically required to accomplish the limitations imposed for food and pharmaceutical products. (3, 5–7, 11, 13, 14). The recent interest in the solvent‐free systems, requiring higher temperatures to improve the substrate solubility and to reduce the viscosity of the reaction medium, has increased the importance of the enzyme stability issue (17).…”

Biocatalytic esterification of β-methylglucoside for synthesis of biocompatible sugar-containing vinyl esters

“…It promotes the reaction between a wide range of alcohols and vinyl ester [2], and is a very heat-tolerant enzyme indicating maximum activity in the range 70-90 • C [3]. Several works have been reported on Novozym 435-catalyzed esterification in solvent-free process as well as in solvent process [4][5][6].…”

Chemo-enzymaticD-enantiomerization ofDL-lactate

“…Most are chemically and microbially manufactured in industry (Rehm and Reed, 1996) and used extensively as key starting materials for the synthesis of various useful compounds (Bousquet et al, 1999). A few chemical methods have been reported for the preparation of optically active 2-hydroxy acids, for example, asymmetric synthesis and optical resolution of the racemate (Holten et al, 1971).…”