AMB Express (Mar 2023)

Immobilization of E. coli expressing γ-glutamyltranspeptidase on its surface for γ-glutamyl compound production

  • Shintaro Arai,
  • Hideyuki Suzuki

DOI
https://doi.org/10.1186/s13568-023-01528-9
Journal volume & issue
Vol. 13, no. 1
pp. 1 – 7

Abstract

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Abstract An Escherichia coli strain expressing γ-glutamyltranspeptidase on its extracellular surface using the Met1 to Arg232 fragment of YiaT of E. coli as an anchor protein was immobilized with alginate for repeated use. Measurement of γ-glutamyltranspeptidase activity of the immobilized cells was performed repeatedly at pH 8.73 and 37 °C for 10 days using γ-glutamyl-p-nitroanilide in the presence of 100 mM CaCl2 and 3% NaCl with and without glycylglycine. Even after the 10th day, the enzyme activity did not decrease from the initial levels. The production of γ-glutamylglutamine from glutamine using the immobilized cells was performed repeatedly at pH 10.5 and 37 °C for 10 days in the presence of 250 mM glutamine, 100 mM CaCl2, and 3% NaCl. Sixty-four % of glutamine was converted to γ-glutamylglutamine in the first cycle. While repeating the production 10 times, the surface of the beads gradually became covered with white precipitate, and the conversion efficiency gradually decreased, but 72% of the initial value still remained even at the 10th measurement.

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