High-level secretion and characterization of cyclodextrin glycosyltransferase in recombinant Komagataella phaffii

- CGTase volumetric activity was significantly increased to 3890 U/ml after codon, vector, and cultivation optimization.
- Fifty β-CGTase left and no γ-CGTase activity of CGTase was detected at 80 °C which was benefit to high purity β-cyclodextrin production.
- The influence of pH and temperature on activity of CGTase from K. phaffii was different to that of native CGTase.

Cyclodextrin glycosyltransferase (CGTase) catalyzes the conversion of starch into cyclodextrin (CD), which is widely applied in food, pharmaceutical, cosmetic, and agricultural industries. For efficient production of CD, high yield of CGTase with good characteristics is necessary. In this study, the cgt gene from Bacillus pseudalcaliphilus was expressed in Komagataella phaffii after codon optimization and expression vector selection. The β-CGTase activity in the transformant reached 3885.1 U mL−1, which is the highest value reported so far, at 28 °C, 6% inoculum ratio, and 1.5% methanol addition following 24 h of incubation. The recombinant CGTase showed high specific activity at 80 °C without any γ-CGTase activity, and had good stability in a wide pH and temperature range. These results demonstrate that the recombinant CGTase could have potential industrial applications.