Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7588640 | Food Chemistry | 2016 | 8 Pages |
Abstract
Industrial application of Caldicellulosiruptor saccharolyticus cellobiose 2-epimerase (CsCE) for lactulose synthesis is limited by low enzyme activity and formation of epilactose as by-product. After four sequential rounds of random mutagenesis and screening, an optimal mutant G4-C5 was obtained. Compared with wild type (WT) enzyme, mutant G4-C5 demonstrated 2.8- and 3.0-fold increases in specific activity and kcat/Km for lactulose production, respectively, without compromising thermostability. DNA sequencing of mutant G4-C5 revealed five amino acid substitutions, namely, R5M, I52V, A12S, K328I and F231L, which were located on the protein surface, except for the mutation I52V. The yield of lactulose catalyzed by mutant G4-C5 increased to approximately 76% with no obvious epilactose detected, indicating that mutant G4-C5 was more suitable for lactulose production than the WT enzyme.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Qiuyun Shen, Yuzhu Zhang, Ruijin Yang, Siyi Pan, Juan Dong, Yuting Fan, Liang Han,