Isolation of Alkyl Glycosides by Adsorption on Active Carbon

Abstract

Active carbon has been widely used as a low-priced adsorbent. However, there are only few applications on isolation of alkyl glycosides. In this paper, adsorption of alkyl glycosides to active carbon and its application in the isolation of alkyl glycosides were investigated. Alkyl β-glucosides and alkyl β-xylosides were used as representatives of alkyl glycosides. The results suggest that the degree of adsorption of both alkyl β-glucoside and alkyl β-xyloside to active carbon increased with the alkyl chain of the glycoside. (Fig.1 and Table 1). Active carbon column chromatography was used for the purification of alkyl β-xyloside (for example isopropyl β-xyloside) which was synthesized by utilizing the transxylosyl activity of Aspergillus niger /3-xylosidase. Stepwise elution with distilled water and 5%(v/v) ethanol solution was employed and 2.3 g of isopropyl β-xyloside was obtained from 10 g of xylobiose (Figs.2 and 3). Furthermore, heptyl p-xyloside, a nonionic surfactant, adsorbed to active carbon irrespective of its concentration and was recovered almost quantitatively from the active carbon when eluted with 50% (v/v) 1-propanol solution (Fig.4). The adsorptive capacity of 1 g (dry weight) of active carbon was approximately O.5 g for heptyl β-xyloside.