Efficient synthesis of a long carbohydrate chain alkyl glycoside catalyzed by cyclodextrin glycosyltransferase (CGTase)

Abstract

Alkyl glycosides with long carbohydrate groups are surfactants with attractive properties but they are very difficult to synthesize. Here, a method for extension of the carbohydrate group of commercially available dodecyl-beta-d-maltoside (DDM) is presented. DDM was converted to dodecyl-beta-d-maltooctaoside (DDMO) in a single step by using a CGTase as catalyst and alpha-cyclodextrin (alpha-CD) as glycosyl donor. The coupling reaction is under kinetic control and the maximum yield depends on the selectivity of the enzyme. The Bacillus macerans CGTase favored the coupling reaction while the Thermoanaerobacter enzyme also catalyzed disproportionation reactions leading to a broader product range. A high ratio alpha-CD/DDM favored a high yield of DDMO and yields up to 80% were obtained using the B. macerans enzyme as catalyst.

β-Glucosidase catalyzed synthesis of octyl-β-d-glucopyranoside using whole cells of Pichia etchellsii in micro aqueous media

“…This synthesis can be achieved through reversed hydrolysis or transglycosylation. Enzymatic synthesis of alkyl glycosides from alcohol and carbohydrate (reversed hydrolysis) works fairly well when both substrates are of moderate size (Svensson et al, 2009). Miscibility problems prevent efficient synthesis as the size of the glycosyl acceptors (longer alcohols) and glycosyl donors (longer carbohydrate part) increases.…”

“…Miscibility problems prevent efficient synthesis as the size of the glycosyl acceptors (longer alcohols) and glycosyl donors (longer carbohydrate part) increases. This presents a challenging problem, since the potential products of such reactions are attractive surfactants and are also very difficult to synthesize by chemical methods (Svensson et al, 2009).…”

Substrate complexation and aggregation influence the cyclodextrin glycosyltransferase (CGTase) catalyzed synthesis of alkyl glycosides

“…In previous studies it has been reported to produce up to 80% of the primary coupling product dodecyl-␤-maltooctaoside (DDMO) from dodecyl-␤-maltoside (DDM) when a high concentration of ␣-cyclodextrin was used as glycosyl donor (Svensson et al, 2009a). When changing the glycosyl donor from ␣-CD to soluble starch, the primary coupling product, DDMO was still the dominating product.…”

Synthesis of Octyl-β-Glucoside Catalyzed by Almond β-Glucosidase in Unconventional Reaction Media

“…Glycosidases, such as alkyl glycosidases, are enzymes that are commonly used for biotechnological production of biodegradable and biocompatible surfactants (7)(8)(9). Some of these long-chained biosurfactants are very diffi cult to synthesise via the usual chemical synthesis because of the incompatibility of the two substrates, the hydrophilic glucose and the hydrophobic alcohol molecule (10,11). The diff erences in solubility of the two substrates are the reason why for a very long time they were synthesised exclusively in two-phase systems with both free and immobilised β-glycosidases, and via both reverse hydrolysis and transglycosylation reactions.…”