International Journal of Molecular Sciences (May 2020)

Combined Optimization of Codon Usage and Glycine Supplementation Enhances the Extracellular Production of a β-Cyclodextrin Glycosyltransferase from <i>Bacillus</i> sp. NR5 UPM in <i>Escherichia coli</i>

  • Nik Ida Mardiana Nik-Pa,
  • Mohamad Farhan Mohamad Sobri,
  • Suraini Abd-Aziz,
  • Mohamad Faizal Ibrahim,
  • Ezyana Kamal Bahrin,
  • Noorjahan Banu Mohammed Alitheen,
  • Norhayati Ramli

DOI
https://doi.org/10.3390/ijms21113919
Journal volume & issue
Vol. 21, no. 11
p. 3919

Abstract

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Two optimization strategies, codon usage modification and glycine supplementation, were adopted to improve the extracellular production of Bacillus sp. NR5 UPM β-cyclodextrin glycosyltransferase (CGT-BS) in recombinant Escherichia coli. Several rare codons were eliminated and replaced with the ones favored by E. coli cells, resulting in an increased codon adaptation index (CAI) from 0.67 to 0.78. The cultivation of the codon modified recombinant E. coli following optimization of glycine supplementation enhanced the secretion of β-CGTase activity up to 2.2-fold at 12 h of cultivation as compared to the control. β-CGTase secreted into the culture medium by the transformant reached 65.524 U/mL at post-induction temperature of 37 °C with addition of 1.2 mM glycine and induced at 2 h of cultivation. A 20.1-fold purity of the recombinant β-CGTase was obtained when purified through a combination of diafiltration and nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography. This combined strategy doubled the extracellular β-CGTase production when compared to the single approach, hence offering the potential of enhancing the expression of extracellular enzymes, particularly β-CGTase by the recombinant E. coli.

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