Molecular modification of Bacillus stearothermophilus NO2 cyclodextrin glucosyltransferase and preparation of α-cyclodextrin
Fangyuan Zuo , Lingqia Su , Demin Kong , Lei Wang , Jing Wu , Sheng Chen
Systems Microbiology and Biomanufacturing ›› 2022, Vol. 2 ›› Issue (4) : 695 -704.
Molecular modification of Bacillus stearothermophilus NO2 cyclodextrin glucosyltransferase and preparation of α-cyclodextrin
Cyclodextrin (CD) is produced by the catalysis of starch or starch derivatives by cyclodextrin glucosyltransferase (CGTase), and its yield is mainly limited by the product and reaction specificity of CGTase. In this study, we use CGTase derived from Bacillus stearothermophilus NO2, exhibiting high expression levels and good stability for molecular modification. The N353A mutant effectively decreases the hydrolysis activity, and the ratio of the k cat values (cyclization to hydrolysis activity) is 86.46, which is threefold that of the wild type. The E142P mutant effectively enhances α-CD specificity, which increases the ratio of k cat values (α-CD to β-CD formation) from 2.18 of the wild-type to 2.42. The N353A/E142P mutant weakens the hydrolysis side reaction and enhances α-CD specificity, and the proportion of α-CD products is 53.67%, which is 15.62% higher than that of the wild-type. This research focuses on CGTase reaction and product specificities, which suggest a novel method for the industrial production of α-CD.
Postgraduate Research & Practice Innovation Program of Jiangsu Province,(KYCX21-2025)
National Natural Science Foundation of China,(31730067)
Agricultural Independent Innovation Fund of Jiangsu Province,(CX(21)3039)
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