Biotechnology Bulletin ›› 2023, Vol. 39 ›› Issue (6): 316-324.doi: 10.13560/j.cnki.biotech.bull.1985.2022-1255

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Increasing the Expression of FAD-dependent Glucose Dehydrogenase by Recombinant Pichia pastoris Using a Combined Strategy

DONG Cong(), GAO Qing-hua, WANG Yue, LUO Tong-yang, WANG Qing-qing   

  1. Hebei Research Institute of Microbiology Co., Ltd., Baoding 071051
  • Received:2022-10-11 Online:2023-06-26 Published:2023-07-07
  • Contact: DONG Cong E-mail:dongcong24@126.com

Abstract:

In order to increase the expression of FAD-dependent glucose dehydrogenase(FAD-GDH)in Pichia pastoris, the recombinant strains of co-expressing different copy numbers of molecular chaperone genes were constructed to achieve high-efficiency expression through the G418 concentration gradient screening, and the shake flask fermentation conditions were optimized. One high-yielding recombinant strain was obtained by G418 concentration gradient screening. On this basis, the recombinant strains co-expressing 1-4 copies of three molecular chaperones, HAC1, Ero1 and PDI, were constructed respectively, and the results of RT-qPCR were in line with expectations. The enzyme activity at the test tube level showed that 3 copies of PDI, 3 copies of HAC1 and 2 copies of Ero1 increased by 83%, 77% and 51%, respectively, compared with 1 copy. The recombinant strain with 3 copies of PDI had the highest enzyme activity, which was 198% higher than the control. The optimal conditions of the recombinant strain were as follows: initial pH 7.0, liquid loading volume 50 mL, the methanol addition amount 1%, and induction temperature 28℃. The efficient expression of FAD-GDH in P. pastoris is achieved by screening of antibiotic concentration and increasing the gene copy number of molecular chaperones.

Key words: FAD-dependent glucose dehydrogenase, Pichia pastoris, antibiotic gradient screening, multiple copies of molecular chaperones