Novel ß-fructofuranosidases from non-conventional yeasts for the synthesis of novel fructosylated derivatives

Abstract

Apart from sucrose hydrolysis, beta-fructofuranosidases (beta-FFases) also catalyze the transfer of the fructose moiety from sucrose to other carbohydrates (called acceptors, including sucrose itself), thus forming homo- and hetero-fructooligosaccharides (FOS) with potential applications in functional foods (prebiotics), pharmaceutical and cosmeceutical industries. Most fungal beta-FFases catalyze the formation of beta(2¿1) linkages between fructose units (inulin-type 1F-FOS, e.g. 1-kestose or nystose). We have isolated, purified, characterized and crystallized several extracellular ¿-fructofuranosidases from cultures of the yeasts Xanthophyllomyces dendrorhous (formerly Phaffia rhodozyma), Schwanniomyces occidentalis and Rhodotorula dairenensis with novel specificities. The ¿-FFase from X. dendrorhous is able to synthesize FOS of the 6G-series (neoFOS, e.g. neokestose and neonystose), which contain a ¿(2¿6) linkage between a fructose and the glucosyl moiety of sucrose.1 In addition, this enzyme fructosylates other disaccharides that contain glucose (maltose, isomaltulose, isomaltose, trehalose) and higher size oligosaccharides (maltotriose, raffinose, maltotetraose).2 S. occidentalis ¿-FFase forms 6F-FOS, which contain ¿(2¿6)-linked fructose units (with a levan-type structure; e.g. 6-kestose).3 The ¿-FFase from R. dairenensis synthesizes a complex mixture of 1F-FOS, 6F-FOS and 6G-FOS.4 The immobilization of several FFases has been also investigated to improve the corresponding bioprocesses.