Comparison of ADH3 promoter with commonly used promoters for recombinant protein production in Pichia pastoris.

Recombinant protein production under the control of the PADH3 was compared with Pichia pastoris PAOX1 and PGAP. The single-copy-clones expressing Aspergillus niger xylanase (XylB) gene with the three different promoters were tested in shake flask and 5 L fed-batch fermentation processes. Recombinant protein production with PADH3, PAOX1 and PGAP were initiated by addition of ethanol, methanol and glucose, respectively in the culture medium. The fermentation process was carried out for 72 h at 30 °C, pH 5 and 30% dissolved oxygen. Extracellular protein production yield for PADH3 (3725 U/mL) was higher than for PAOX1 (2095 U/mL) and PGAP (580 U/mL) at fermentor scale under the conditions tested. These results show that the PADH3 promoter is a promising tool for large scale production of recombinant proteins and can be an alternative to the PAOX1 and PGAP.