Synthesis of alkyl glycosides by transglycosylation reaction of cyclodextrin glycosyltransferase

Name: Rittichai Charoensapyanan

keyword: Antibacterial activity

; Cyclodextrin glycosyltransferase

; Emulsifying properties

; Insoluble protein solubilization

; Isopentyl glycosides

; Pentyl glycosides

; Propyl glycosides

Abstract: Alkyl glycosides are non-ionic surfactants which have been applied in a variety of household, industrial, biotechnological and pharmaceutical levels. In this study, alkyl glycosides of propyl glycosides (ProGn), pentyl glycosides (PenGn) and isopentyl glycosides (IsoPenGn) were enzymatically synthesized by recombinant cyclodextrin glycosyltransferase (CGTase) from Bacillus circulans A11 using β-cyclodextrin as donor and 1-propanol, 1-pentanol and isopentanol as acceptors. When the reaction products were analyzed by thin layer chromatography (TLC), it was found that each alcohol acceptor gave at least three alkyl glycoside products. These products were assumed to be alkyl glycoside derivatives having one to three glucose units attached to the alkyl groups of each alcohol. After the reactions were optimized and prepared in larger scale, the 37, 48 and 42% (w/w) yields of ProGn, PenGn and IsoPenGn were obtained, respectively. Two products of each glycoside derivative were then isolated by preparative TLC and their structures were identified by the combination of amylolytic enzymes treatment, mass spectrometry and NMR analyses to be propyl-α-D-glucopyranoside (ProG1), propyl-α-D-maltopyranoside (ProG2), pentyl-α-D-glucopyranoside (PenG1), pentyl-α-D-maltopyranoside (PenG2), isopentyl-α-D-glucopyranoside (IsoPenG1) and isopentyl-α-D-maltopyranoside (IsoPenG2). The emulsifying properties of the synthesized products were determined by measuring their ability to form and stabilize oil-in-water emulsion using n-hexadecane as substrate. The results showed that PenG2 was the best emulsifying agent as compared to the other synthesized products. The antibacterial activity of the synthesized products was also tested by disc diffusion technique, minimal inhibitory concentration and minimal bactericidal concentration against Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922. The results revealed that the structure and length of alkyl chain and the number of glucose had an effect on the antibacterial activity of alkyl glycosides. PenG2 which contained linear primary pentyl chain and disaccharide exhibited the highest antibacterial activity and was the most effective agent for inhibiting E. coli growth. Furthermore, the addition of PenG2 to the insoluble Corynebacterium glutamicum amylomaltase protein during cell lysis resulted in the increasing of both solubility and activity of amylomaltase. From these biological properties, it can be concluded that these synthesized alkyl glycosides could be applied for the use as emulsifying, antibacterial and insoluble protein solubilizing agents

Thammasat University. Thammasat University Library

Address: BANGKOK

Email: preserv@tu.ac.th

Name: Jarunee Kaulpiboon

Role: advisor

Created: 2016

Modified: 2021-07-15

Issued: 2021-07-15

วิทยานิพนธ์/Thesis

application/pdf

DOI: 10.14457/TU.the.2016.1472

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Biochemistry and Molecular Biology

Grantor: Thammasat University

©copyrights Thammasat University

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