Naturally occurring novel promoters around pyruvate branch-point for recombinant protein production in Pichia pastoris (Komagataella phaffii): Pyruvate decarboxylase- and pyruvate kinase- promoters

Massahi A., ÇALIK P.

BIOCHEMICAL ENGINEERING JOURNAL, vol.138, pp.111-120, 2018 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 138
  • Publication Date: 2018
  • Doi Number: 10.1016/j.bej.2018.07.012
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.111-120
  • Keywords: Pichia pastoris (Komagataella phaffii), Pyruvate decarboxylase promoter, Pyruvate kinase promoter, Transcription, Recombinant protein, Flux distributions, GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE PROMOTER, METABOLIC FLUX ANALYSIS, OXYGEN-TRANSFER, BACILLUS-LICHENIFORMIS, SYNTHETIC BIOLOGY, EXPRESSION, FERMENTATION, OPTIMIZATION, STRATEGIES, CULTURES


Novel strong promoter discovery is crucial for the design of novel strains of the industrial yeast Pichia pastoris for recombinant protein (r-protein) production. In order to remedy the deficiency, transcriptome and proteome data of P. pastoris were analysed. Genes having higher expression levels than glyceraldehyde-3-phosphate-dehydrogenase (GAP) gene were identified as promoter sources. Pyruvate kinase- (P-PYK) and pyruvate decarboxylase- (P-PDC) promoters around pyruvate-node were determined as promising candidates, and in silico analysis of the putative promoter regions was performed. The putative promoters were introduced into the plasmid pGAPZ alpha A::hGH harboring human growth hormone (hGH) gene, instead of P-GAP. Single-copy hGH gene carrying strains under P-PYK P-PDC, and for comparison under P-GAP were tested in high-cell-density rhGH fermentations, respectively, abbreviated as BRPYK, BRPDC. and BRGAP. Comparative promoter strength assessment was made by the mRNA-transcription-copy-number (mTCN) and r-protein concentration measurements, and by constrained flux analysis. P-PDC and P-PYK exhibited higher activity compared to P-GAP. Highest rhGH titer was obtained in BRPDC as 122 mg dm(-3) at t=15 h, in BRPYK as 101 mg dm(-3) at t=12 h, and in BRGAP as 58 mg dm(-3) at t=9 h; while, with P-PDC and P-GAP the mTCNs were high and close. The flux distributions demonstrated regulatory effects of the novel promoters in the engineered strains and validated cross-pathway regulatory interactions. (C) 2018 Elsevier B.V. All rights reserved.