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

Dodecyl glucooligosides, a class of interesting non ionic surfactant molecules were synthesized by cyclodextrin glucanotransferase from Bacillus macerans using either alpha-cyclodextrin (alpha-CD) or soluble starch as glycosyl donor and dodecyl beta-D-glucoside (C(12)G(1)) or dodecyl beta-D-maltoside (C(12)G(2)) 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 alpha-CD as donor, while more dispoportionation occurred with starch. Nearly 78% conversion of the acceptor substrate C(12)G(1) into dodecyl glucooligosides could be achieved at 132 mu g/ml of CGTase in 20 min, while 93% of C(12)G(2) could be transformed into products at 17.6 mu g/ml of enzyme in 120 min using soluble starch as donor substrate. For applications requiring pure compounds like C(12)G(7), synthesis using alpha-CD is advantageous. However, for applications in which a mixture of elongated alkyl glycosides is needed, reactions employing starch are clearly competitive. (C) 2011 Elsevier Ltd. All rights reserved