n-Octyl beta-D-xylotrioside, xylobioside and xyloside, which are effective next-generation surfactants, can be prepared by the one-step reaction of xylan and n-octanol using the acetone powder (acetone-dried cells) of Aureobasidium pullulans as the enzyme source of xylanase in supercritical carbon dioxide (CO2) and fluoroform (CHF3) fluids. Yields of the n-octyl glycosides were significantly increased using supercritical CHF3, and the total yields of the n-octyl beta-D-glycosides exceeded 250 mg g(-1) xylan. n-Octyl beta-D-xylotrioside was produced only by using supercritical fluids.