Enhancement of cyclodextrin production through use of debranching enzymes

In the presence of a complexant and a debranching enzyme capable of cleaving a‐(1 6) linkages in a‐D‐glucans, Bacillus mascerans cyclodextrin glucanotransferase (CGTase; EC 2.4.1.19) converted starch, maltodextrin and glycogen into cyclodextrin (CD) in yields higher than those obtainable in the absence of debranching enzyme. The extent of yield enhancement by pullulanase (EC 3.2.1.41; from Enterobacter aerogenes ) was dependent upon temperature, type of substrate (including source of starch) and kind of complexant. Highest yields with pullulanase were attained generally by use of low temperature (15Ő25 ° C) and starches of low amylose content. At 25 ° C and pH 7, with cyclodecanone as complexant, 91Ő93% yields of b‐CD were obtainable from amylopectin, waxy‐maize starch, and tapioca starch. With decan‐1‐ol as complexant, amylopectin was converted at 15 ° C into a‐CD in 84% yield. With cyclotridecanone as complexant, amylopectin was converted at 40 ° C into ‐CD in 72% yield. The debranching enzyme isoamylase (EC 3.2.1.68; from Pseudomonas amyloderamosa ) was also employed successfully to achieve high b‐CD yields. A 90% yield of b‐CD from amylopectin was obtained by applying isoamylase, CGTase and cyclodecanone at pH 6 and 25 ° C.