Abstract:To alleviate the dissolved oxygen (DO) limitation and improve Candida antarctica lipase B (CALB) production during high-cell density fermentation, the CALB gene and Vitreoscilla hemoglobin (VHb) gene vgb were co-expressed in Pichiapastoris under the AOX1 and YPT promoter control, respectively. In addition, to detect the effect of signal peptide, GFP was expressed on the surface of peroxide, while RFP was expressed in the peroxide matrix. Finally, GFP or RFP was replaced by VHb protein to find out the impaction of the different positions. SDS-PAGE and Western Blot analysis results indicated that VHb and CALB were successfully co-expressed in recombinant strains. Compared with the control strain, expression of CALB in GS115/ExVHb and GS115/VHbSKL under oxygen limitation was improved by 27.57% and 20.52%, respectively. Therefore, expression of VHb in P. pastoris is an effective strategy to improve CALB production.
