Enzyme-catalyzed synthesis of alkyl-beta-glucosides in a water-alcohol two-phase system.
The enzymic synthesis of alkyl-beta-glucosides by water-immiscible alcohols was studied in stirred flasks as well as in a tubular enzymatic reactor. In the first case, direct alkylation of beta-D-glucose from hexanol using immobilized beta-glycosidase gave a higher conversion yield and final product concentration than that using the enzyme in its free state (yield 10 against 8% mol/mol, concentration 2 against 1.6 g/l). Direct glycosylation of beta-D-glucose from hexanol resulted in a higher reaction performance (yield 10%) than that from octanol (yield 5%). However, the two different incubation temperatures tested (37 degrees C and 50 degrees C), showed no significant differences concerning final product concentrations. The more interesting results were obtained by transglycosylation of methyl-1-beta-glucose from hexanol, with a conversion yield of 21% mol/mol (product amount 4 g/l). However, the transgalactosylation of lactose from hexanol, catalyzed by a fungal beta-galactosidase, showed only a feeble reactivity. The feasibility of enzymic alkylation was also tested in a tubular enzymatic reactor; hexyl-1-beta-glucoside was produced via direct glycosylation from hexanol catalyzed by free beta-glycosidase with a final concentration 1.3-2.3 g/l and a yield varying between 11% and 20% mol/mol.
Papanikolaou
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Laboratoire des Sciences du Génie Chimique-CNRS,-ENSAIA, UPR 6811, 2, Avenue de la forêt de Haye, 54505 Vandoeuvre-Lès-Nancy, France. cbalis@aua.gr
D000438:Alcohols / Q000737:chemistry*; D000478:Alkylation; D002384:Catalysis; D004800:Enzymes, Immobilized; D005947:Glucose / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D005960:Glucosides / Q000138:chemical synthesis* / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000378:metabolism*; D000441:Hexanols / Q000737:chemistry / Q000378:metabolism; D007785:Lactose / Q000737:chemistry / Q000378:metabolism; D000442:Octanols / Q000737:chemistry / Q000378:metabolism; D014867:Water / Q000737:chemistry*
D000438:Alcohols; D004800:Enzymes, Immobilized; D005960:Glucosides; D000441:Hexanols; D000442:Octanols; D014867:Water; D006026:Glycoside Hydrolases; D005947:Glucose; D007785:Lactose