Use of the yeast Hansenula polymorpha ( Pichia angusta) to remove contaminating sugars from ethyl β- d-fructofuranoside produced during sucrose ethanolysis catalysed by invertase

Abstract

Alkyl glycosides are interesting intermediates for the production of biodegradable surfactants. Synthesis of ethyl β- d-fructofuranoside by invertase-catalysed ethanolysis of sucrose has been extensively reported in literature. However, this procedure yields mixtures of glucose, fructose, sucrose and ethyl β- d-fructofuranoside. Purification of ethyl β- d-fructofuranoside from such mixtures by chromatographic methods is laborious, difficult to scale up and requires organic solvents. The yeast Hansenula polymorpha grows rapidly on glucose, fructose and sucrose. Sucrose hydrolysis in this yeast is catalysed by an intracellular α-glucosidase (‘maltase’); consequently, H. polymorpha should be unable to hydrolyse ethyl β- d-fructofuranoside. Indeed, aerobic cultivation of H. polymorpha on sugar mixtures obtained by invertase-catalysed ethanolysis of sucrose resulted in the complete removal of contaminating sugars, leaving ethyl β- d-fructofuranoside as the sole organic compound in culture supernatants. Pure ethyl β- d-fructofuranoside was recovered from the supernatants by mixed-bed ion exchange chromatography with an 86% yield.