Heterologous expression of Streptomyces coelicolor trehalose synthase and whole-cell biocatalyst production of trehalose in Escherichia coli / 生物工程学报
Chinese Journal of Biotechnology
;
(12): 1348-1358, 2019.
Article
in Chinese
| WPRIM
| ID: wpr-771794
ABSTRACT
The trehalose synthase (ScTreS) gene from Streptomyces coelicolor was successfully cloned and heterologously expressed in Escherichia coli BL21(DE3). The protein purified by Ni-NTA affinity column showed an apparent molecular weight (MW) of 62.3 kDa analyzed by SDS-PAGE. The optimum temperature of the enzyme was 35 °C and the optimum pH was 7.0; the enzyme was sensitive to acidic conditions. By homologous modeling and sequence alignment, the enzyme was modified by site-directed mutagenesis. The relative activities of the mutant enzymes K246A and A165T were 1.43 and 1.39 times that of the wild type, an increased conversion rate of 14% and 10% respectively. To optimize the synthesis conditions of trehalose, the mutant strain K246A was cultivated in a 5-L fermentor and used for whole-cell transformation. The results showed that with the substrate maltose concentration of 300 g/L at 35 °C and pH 7.0, the highest conversion rate reached 71.3%, and the yield of trehalose was 213.93 g/L. However, when maltose concentration was increased to 700 g/L, the yield of trehalose can reach 465.98 g/L with a conversion rate of 66%.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Trehalose
/
Cloning, Molecular
/
Streptomyces coelicolor
/
Escherichia coli
/
Biocatalysis
/
Glucosyltransferases
Language:
Chinese
Journal:
Chinese Journal of Biotechnology
Year:
2019
Type:
Article
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