The transglycosylation activity of a novel a-glucosidase from the basidiomycetous yeast Xanthophyllomyces dendrorhous (formerly Phaffia rhodozyma) was studied using maltose as glucosyl donor. The enzyme synthesized oligosaccharides with a-(1 ! 2), a-(1 ! 4) and a-(1 ! 6) bonds. Using 200 g/l maltose, the yield of oligosaccharides was 53.8 g/l, with prebiotic oligosaccharides containing at least one a-(1 ! 6) linkage (panose, 6-O-a-glucosyl-maltotriose and 6-O-a-isomaltosyl-maltose) being the major products (47.1 g/l). The transglycosylatying yield was 3.6 times higher than the observed with the a-glucosidase from Saccharomyces cerevisiae (53.8 vs. 14.7 g/l). Moreover, when increasing the maltose concentration up to 525 g/l, the maximum production of tri-and tetrasaccharides reached 167.1 g/l, without altering the percentage of oligosaccharides in the mixture. Compared with other microbial a-glucosidases in which the main transglycosylation product is a disaccharide, the enzyme from X. dendrorhous yields a final product enriched in trisaccharides and tetrasaccharides. #
An extracellular beta-fructofuranosidase from the yeast Rhodotorula dairenensis was characterized biochemically. The enzyme molecular mass was estimated to be 680 kDa by analytical gel filtration and 172 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, of which the N-linked carbohydrate accounts for 16% of the total mass. It displays optimum activity at pH 5 and 55-60 degrees C. The enzyme shows broad substrate specificity, hydrolyzing sucrose, 1-kestose, nystose, leucrose, raffinose and inulin. Although the main reaction catalyzed by this enzyme is sucrose hydrolysis, it also exhibits transfructosylating activity that, unlike other microbial beta-fructofuranosidases, produces a varied type of prebiotic fructooligosaccharides containing beta-(2-->1)- and beta-(2-->6)-linked fructose oligomers. The maximum concentration of fructooligosaccharides was reached at 75% sucrose conversion and it was 87.9 g L(-1). The 17.0% (w/w) referred to the total amount of sugars in the reaction mixture. At this point, the amounts of 6-kestose, neokestose, 1-kestose and tetrasaccharides were 68.9, 10.6, 2.6 and 12.7 g L(-1), respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.