Abstract
Abstract: a-Galactosidases from Aspergillus niger APC-9319 and Candida guilliermondii H-404 efficiently catalyzed the transgalactosylation to allyl alcohol. In the case of C. guilliermondii H-404 α-galactosidase, the yield of a main transfer product to allyl alcohol P2 correspondingly increased with the increase of allyl alco-hol concentration. The maximum yield of P2 (250 mM) was obtained with conditions of 35% (v/v) allyl alco-hol and 0.6 M melibiose. On the other hand, in Asp. niger APC-9319 α-galactosidase, the yield of P2 reached a maximum with 17.5% (v/v) allyl alcohol concentration. At more than 20% (v/v) allyl alcohol, the amount of P2 decreased because the allyl alcohol inhibited the enzyme activity. P2 was confirmed to be allyl α-D-galactopyranoside by enzymatic hydrolysis and 13C-NMR analysis. Furthermore, Asp. niger APC-9319 and C. guilliermondii H-404 α-galactosidases catalyzed the transgalactosylation to allyl α-galactopyranoside. The yield of transfer product to allyl α-galactopyranoside by Asp. niger APC-9319 α-galactosidase was higher than that by C. guilliermondii H-404 α-galactosidase. The maximum yield was approximately 20% of the weight (g) of allyl α-galactopyranoside used. The transfer product to allyl a-galactopyranoside was separated into three peaks named a, b and c. The structures of a and b were confirmed to be allyl 6-O-α-D-galactopyranosyl-6-O -α-D-galactopyranosyl-α-D-galactopyranoside and allyl 6-O-α-D-galactopyranosyl-α-D-galactopyranoside, respectively, by enzymatic hydrolysis and 13C-NMR analysis. The structure of c was estimated to be allyl 3-O -α-D-galactopyranosyl-α-D-galactopyranoside.
