| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 17341 | Enzyme and Microbial Technology | 2012 | 7 Pages |
The Yarrowia lipolytica lipase LIP2 (YlLIP2) gene lip2 and Vitreoscilla hemoglobin gene vgb were co-expressed in Pichia pastoris, both under the control of AOX1 promoter, in order to alleviate respiration limitation under conditions of high cell-density fermentation and enhance YlLIP2 production. The results showed that recombinant P. pastoris strains harboring the lip2 and vgb genes (VHb+) displayed higher biomass and YlLIP2 activity than control strains (VHb−). Compared with VHb− cells, the expression levels of YlLIP2 in VHb-expressing cells when oxygen was not a limiting factor were improved 31.5% in shake-flask culture and 22% in a 10-L fermentor. Under non-limiting dissolved oxygen (DO) conditions, the maximum YlLIP2 activity of VHb+ in a 10-L fermentor reached 33,000 U/mL. Oxygen limitation had a more negative effect on YlLIP2 productivity in VHb− cells than in VHb+ cells. The highest YlLIP2 activity of VHb+ cells was approximately 1.84-fold higher than that of VHb− cells at lower DO levels. Moreover, the recombinant strain VHb+ exhibited a higher specific oxygen uptake rate and achieved higher cell viability under oxygen limiting and non-limiting conditions compared with VHb− cells. Therefore, the above results suggest that intracellular expression of VHb in recombinant P. pastoris has the potential to improve cell growth and industrial enzyme production.
► Lipase gene and Vitreoscilla hemoglobin gene were co-expressed in Pichia pastoris. ► Recombinant strain (VHb+) exhibited high specific oxygen uptake rate. ► VHb+ strain displayed higher biomass and lipase activity than control strains. ► The maximum lipase activity of VHb+ in a 10-L fermentor reached 33,000 U/mL. ► VHb+ strain also achieved higher cell viability than control strain.
