Cyclodextrin glucanotransferase (CGTase) catalyzed synthesis of dodecyl glucooligosides by transglycosylation using [alpha]-cyclodextrin or starch

Dodecylglucooligosides, a class of interesting non ionic surfactant molecules were synthesized by cyclodextringlucanotransferase from Bacillus macerans using either a-cyclodextrin (a-CD) or soluble starch as glycosyl donor and dodecyl ß-d-glucoside (C12G1) or dodecyl ß-d-maltoside (C12G2) as acceptor substrates. The primary coupling products obtained in the respective reactions were identified as dodecyl glucoheptaoside and dodecyl maltooctaoside by mass spectrometry. Higher yields of coupling products were obtained using a-CD as donor, while more dispoportionation occurred with starch. Nearly 78% conversion of the acceptor substrate C12G1 into dodecylglucooligosides could be achieved at 132 µg/ml of CGTase in 20 min, while 93% of C12G2 could be transformed into products at 17.6 µg/ml of enzyme in 120 min using soluble starch as donor substrate. For applications requiring pure compounds like C12G7, synthesis using a-CD is advantageous. However, for applications in which a mixture of elongated alkyl glycosides is needed, reactions employing starch are clearly competitive.