title: The production of alpha-cyclodextrin by enzymatic degradation of starch.
abstract: The maximum concentration of alpha-cyclodextrin for the enzymatic degradation of starch is limited to about 13.5 g X 1(-1). By addition of decanol, the equilibrium of the reaction system can be shifted towards an alpha-cyclodextrin yield of 50% even at high substrate concentrations. The main variables of the decanol process--pH, temperature, substrate quality, substrate, and enzyme concentration--have been studied. The cyclodextrin-glycosyltransferase from Klebsiella pneumoniae M5 al can preferentially be employed at pH 6 to 8, temperatures of 40 to 50 degrees C and a decanol concentration of 0.1 kg-1 starch. The dextrose equivalent of starch is important with respect to the maximum achievable starch concentration, but not with respect to the reaction. Under process conditions, the rate of alpha-cyclodextrin evolution is limited by the enzymatic reaction and not by mass transfer of decanol into the aqueous phase.
mesh_terms: D003505:Cyclodextrins / Q000096:biosynthesis*; D003912:Dextrins / Q000096:biosynthesis*; D005233:Fatty Alcohols / Q000494:pharmacology; D005964:Glucosyltransferases / Q000378:metabolism*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007711:Klebsiella pneumoniae / Q000201:enzymology*; D011489:Protein Denaturation; D013213:Starch / Q000096:biosynthesis* / Q000378:metabolism*; D047391:alpha-Cyclodextrins
chemical_list: D003505:Cyclodextrins; D003912:Dextrins; D005233:Fatty Alcohols; D047391:alpha-Cyclodextrins; C029383:n-decyl alcohol; D013213:Starch; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase; C032613:alpha-cyclodextrin