Enzymatic synthesis of butyl glucoside by beta-glucosidase from bitter almonds was optimized using response surface methodology (RSM). Empirical models were developed to describe relationships between the operating variables (temperature, water/butanol volume ratio, glucose concentration, enzyme concentration) and responses (butyl glucoside concentration, conversion yield). Statistical analysis indicated that the four factors had significant effects on the butyl glucoside synthesis. Optimal concentration (41.6 g/L) was reached when the operating conditions were temperature (44.7 degrees C), water/butanol volume ratio (17.6%), glucose concentration (199.2 g/L), and enzyme concentration (2.5 g/L). Good agreement between predicted and measured data at the predicted optimal conditions confirmed the usefulness of the model. Synthesis at a laboratory pilot scale was successful.