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

• Published in: Biotechnology and bioengineering 1999-01, Vol.62 (2), p.225-234
• Main Authors: Bousquet, Marie-Pierre, Willemot, René-Marc, Monsan, Pierre, Boures, Emmanuel
• Format: Article
• Language: English
• Subjects: Bioconversions. Hemisynthesis; Biological and medical sciences; Bioreactors; Biotechnology; Candida - enzymology; Enzyme immobilization; Enzymes, Immobilized; Esterification; Fundamental and applied biological sciences. Psychology; Glucosides - metabolism; Grafting (chemical); Hydrolysis; Lactates - metabolism; lactic acid; Lipase; Lipase - isolation & purification; Lipase - metabolism; Magnetic Resonance Spectroscopy; Methods. Procedures. Technologies; Nuclear magnetic resonance spectroscopy; Organic acids; organic synthesis; Phase equilibria; Pressure; Proteins; Rhizomucor - enzymology; Solubility; Solvents; Sugar Acids - chemistry; Sugar Acids - metabolism; Synthesis (chemical); Temperature; transesterification; Water; α-butylglucoside
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/(SICI)1097-0290(19990120)62:2<225::AID-BIT13>3.0.CO;2-#

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.