Oxygen transfer as a tool for fine-tuning recombinant protein production by Pichia pastoris under glyceraldehyde-3-phosphate dehydrogenase promoter


Gunes H., ÇALIK P.

BIOPROCESS AND BIOSYSTEMS ENGINEERING, vol.39, no.7, pp.1061-1072, 2016 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 39 Issue: 7
  • Publication Date: 2016
  • Doi Number: 10.1007/s00449-016-1584-y
  • Journal Name: BIOPROCESS AND BIOSYSTEMS ENGINEERING
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.1061-1072
  • Keywords: Oxygen transfer, Fed-batch culture, Bioprocess design, Fermentation, Pichia pastoris, GAP promoter, METHANOL FEEDING STRATEGY, GROWTH-HORMONE PRODUCTION, HIGH-LEVEL EXPRESSION, BACILLUS-LICHENIFORMIS, GAP PROMOTER, GENE, PARAMETERS, SYSTEM

Abstract

Effects of oxygen transfer on recombinant protein production by Pichia pastoris under glyceraldehyde- 3-phosphate dehydrogenase promoter were investigated. Recombinant glucose isomerase was chosen as the model protein. Two groups of oxygen transfer strategies were applied, one of which was based on constant oxygen transfer rate where aeration rate was Q(O)/V = 3 and 10 vvm, and agitation rate was N = 900 min(-1); while the other one was based on constant dissolved oxygen concentrations, C-DO = 5, 10, 15, 20 and 40 % in the fermentation broth, by using predetermined exponential glucose feeding with mu(o) = 0.15 h(-1). The highest cell concentration was obtained as 44 g L-1 at t = 9 h of the glucose fed-batch phase at C-DO = 20 % operation while the highest volumetric and specific enzyme activities were obtained as 4440 U L-1 and 126 U g(-1) cell, respectively at C-DO = 15 % operation. Investigation of specific enzyme activities revealed that keeping C-DO at 15 % was more advantageous with an expense of relatively higher byproduct formation and lower specific cell growth rate. For this strategy, the highest oxygen transfer coefficient and oxygen uptake rate were K(L)a = 0.045 s(-1) and OUR = 8.91 mmol m(-3) s(-1), respectively.