n-Hexyl-beta-D-glucopyranoside (HGP) was synthesized through the beta-glucosidase-catalyzed condensation of glucose and hexanol in an aqueous-organic bicontinuous microemulsion system with both water and oil as continuous phases. Methodology for separation of HGP from the microemulsion system for analysis by gas chromatography was developed. Various factors influencing the synthesis of HGP like reaction time, enzyme concentration and temperature were optimized experimentally. P-Glucosidase (1.1 U/ml) yielded a final HGP concentration of 6.5 mM at 45 degrees C after 24 h reaction. Reverse reaction (hydrolysis) occurred was also studied. Comparison of the rate of the reaction between synthesis and hydrolysis showed the latter to be faster, suggesting that bicontinuous microemulsion system is more applicable to the enzymatic hydrolysis. Degradation of enzyme in bicontinuous microemulsion system was very negligible. (c) 2007 Elsevier Inc. All rights reserved.