Secretion of water soluble pyrroloquinoline quinone glucose dehydrogenase by recombinant Pichia pastoris

Secretory production of water soluble pyrroloquinoline quinone glucose dehydrogenase (PQQGDH-B) from Acinetobacter calcoaceticus was carried out by using recombinant Pichia pastoris. PQQGDH-B is periplasmic protein by processing signal peptide posttranslational process in A. calcoaceticus. Instead of the native signal sequence of PQQGDH-B, Saccharomyces cerevisiae α-factor signal sequence was used for secretion of PQQGDH-B in Pichia pastoris in this study. The productivity of secreted PQQGDH-B achieved 218 kU/liter (43 mg/liter) which is almost the same level as that of recombinant PQQGDH-B previously produced in E. coli. The secreted PQQGDH-B in P. pastoris was glycosylated but showed similar enzymatic properties as compared with those of recombinant PQQGDH-B produced in E. coli. Considering the further optimization of the down stream process and culture condition for high-level production of the recombinant PQQGDH-B by P. pastoris, this expression system is expected to achieve industrial level production.