Intracellular expression of Vitreoscilla hemoglobin improves production of Yarrowia lipolytica lipase LIP2 in a recombinant Pichia pastoris

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• 作者：Xiaofeng Wang ; Yongchuan Sun ; Xuguang Shen ; Feng Ke ; Heyun Zhao ; Yun Liu ; Li Xu ; Yunjun Yan  ; ;   ; ^{yanyunjun@mail.hust.edu.cn} ;   ; ^{yanyunjun@tom.com}
• 关键词：Expression ; Lipase ; Pichia pastoris ; Vitreoscilla hemoglobin ; Yarrowia lipolytica
• 刊名：Enzyme and Microbial Technology
• 出版年：2012
• 出版时间：5 January 2012
• 年：2012
• 卷：50
• 期：1
• 页码：22-28
• 全文大小：664 K

文摘

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^{?/sup>). Compared with VHb?/sup> 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?/sup> cells than in VHb+ cells. The highest YlLIP2 activity of VHb+ cells was approximately 1.84-fold higher than that of VHb?/sup> 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?/sup> 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.}