499-40-1Relevant articles and documents
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Thompson et al.
, p. 1309 (1954)
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Development of a multiphase reaction system for integrated synthesis of isomaltose with a new glucosyltransferase variant
Erhardt, Frank A.,Rosenstock, Philip,Hellmuth, Hendrik,Joerdening, Hans-Joachim
, p. 72 - 82 (2010)
A new genetically derived variant of the glucosyltransferase from Streptococcus oralis has been characterized physicochemically and kinetically. Compared with the industrially used glucosyltransferase from Leuconostoc mesenteroides, the enzyme variant GTF-R S628D possesses 25 times higher affinity for the specific glucosylation of glucose. For a concept of integrated reaction and product isolation, a fluidized bed reactor with in situ product removal was applied. The technical feasibility and the applicability of the kinetic models for reaction and adsorption could be demonstrated. The immobilized enzyme was stable (20% activity loss after 192 h) and product could be obtained with 90% purity. A bioprocess model was generated which allowed the integral assessment of the enzymatic synthesis and in situ product adsorption. The model is a powerful tool which assists with the localization of optimal process parameters. It was applied for the process evaluation of other glucosyltransferases and demonstrated key characteristics of each enzymatic system.
Heterologous expression of a thermostable α-glucosidase from Geobacillus sp. Strain HTA-462 by Escherichia coli and its potential application for isomaltose–oligosaccharide synthesis
Zhang, Fan,Wang, Weiyang,Bah, Fatoumata Binta Maci,Song, Chengcheng,Zhou, Yifa,Ji, Li,Yuan, Ye
, (2019/05/02)
Isomaltose–oligosaccharides (IMOs), as food ingredients with prebiotic functionality, can be prepared via enzymatic synthesis using α-glucosidase. In the present study, the α-glucosidase (GSJ) from Geobacillus sp. strain HTA-462 was cloned and expressed in Escherichia coli BL21 (DE3). Recombinant GSJ was purified and biochemically characterized. The optimum temperature condition of the recombinant enzyme was 65 ?C, and the half-life was 84 h at 60 ?C, whereas the enzyme was active over the range of pH 6.0–10.0 with maximal activity at pH 7.0. The α-glucosidase activity in shake flasks reached 107.9 U/mL and using 4-Nitrophenyl β-D-glucopyranoside (pNPG) as substrate, the Km and Vmax values were 2.321 mM and 306.3 U/mg, respectively. The divalent ions Mn2+ and Ca2+ could improve GSJ activity by 32.1% and 13.8%. Moreover, the hydrolysis ability of recombinant α-glucosidase was almost the same as that of the commercial α-glucosidase (Bacillus stearothermophilus). In terms of the transglycosylation reaction, with 30% maltose syrup under the condition of 60 ?C and pH 7.0, IMOs were synthesized with a conversion rate of 37%. These studies lay the basis for the industrial application of recombinant α-glucosidase.
Transglycosylation properties of maltodextrin glucosidase (MalZ) from Escherichia coli and its application for synthesis of a nigerose-containing oligosaccharide
Song, Kyung-Mo,Shim, Jae-Hoon,Park, Jong-Tae,Kim, Sung-Hee,Kim, Young-Wan,Boos, Winfried,Park, Kwan-Hwa
experimental part, p. 87 - 92 (2011/10/18)
The transglycosylation reaction of maltodextrin glucosidase (MalZ) cloned and purified from Escherichia coli K12 was characterized and applied to the synthesis of branched oligosaccharides. Purified MalZ preferentially catalyzed the hydrolysis of maltodextrin, γ-cyclodextrin (CD), and cycloamylose (CA). In addition, when the enzyme was incubated with 5% maltotriose (G3), a series of transfer products were produced. The resulting major transfer products, annotated as T1, T2, and T3, were purified and their structures were determined by TLC, MALDI-TOF/MS, 13C NMR, and enzymatic analysis. T1 was identified as a novel compound, maltosyl α-1,3-maltose, whereas T2 and T3 were determined to be isopanose and maltosyl-α-1,6-maltose, respectively. These results indicated that MalZ transferred sugar moiety mainly to C-3 or C-6-OH of glucose of the acceptor molecule. To obtain highly concentrated transfer products, the enzyme was reacted with 10% liquefied cornstarch, and then glucose and maltose were removed by immobilized yeast. The T1 content of the resulting reaction mixture reached 9.0%. The mixture of T1 containing a nigerose moiety can have an immunopotentiating effect on the human body and may be a potential functional sugar stuff.