文献类型： 外文期刊
作者： Guo, Mei-Jin 1 ; Zhuang, Ying-Ping 1 ; Chu, Ju 1 ; Zhang, Si-Liang 1 ; Xiongc, Ai-Sheng 3 ; Pengc, Ri-He 3 ; Yaoc, Qua 1 ;
作者机构： 1.E China Univ Sci & Technol, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China
2.Jiangxi Agr Univ, Dept Biotechnol, Nanchang 330045, Peoples R China
3.Shanghai Acad Agr, Res Ctr Agrobiotechnol, Shanghai 201106, Peoples R China
关键词： pichia pastoris FPHY34;fermentation process optimization;respiratory quotient monitoring;phosphate effect;separation and purification of phytase
期刊名称：PROCESS BIOCHEMISTRY （ 影响因子：3.757； 五年影响因子：3.665 ）
ISSN：
年卷期：
页码：
收录情况： SCI
摘要： A genetically engineered Pichia pastoris FPHY34 strain containing a 1.3 kb thermostable phytase gene (fphy) evolved by DNA shuffling was constructed and screened. Expression and purification conditions for the recombinant phytase were developed in this study. The effect of Pi on recombinant phytase expression and cell growth of P. pastoris FPHY34 was tested in shake flask culture. Optimization of carbon sources for cell growth and methanol feeding strategies for phytase expression in P. pastoris FPHY34 was carried out in a 50-L fermenter by fed-batch fermentation. The purification of phytase was investigated by micro-filtration and ultra-filtration followed by desalting, ion-exchange chromato-graphy, and gel filtration in the AEKTA system. It showed that the optimum inorganic phosphorus is 13.6 g L~(-1) and that glucose can be used as a substrate for P. pastoris cell growth instead of glycerol; the biomass yield of glycerol (Y_(X/S)) is slightly higher than that of glucose. Different profiles of lag phase and respiratory quotient (RQ) displayed between glucose and glycerol as the sole carbon source. The maximum phytase activity in per millimetre reached 2508 U mL~(-1) at a methanol feed rate of 3.0 mL L~(-1) h~(-1) after 80 h period of induction. A purification factor of 41.1 with a 32% yield was achieved after chromatographic purification. The specific enzyme activity was 80 U mg~(-1) and 3281 U mg~(-1) in that supernatant fraction and after eel filtration purification, respectively. The strain P. pastoris FPHY34 showed a promising application in phytase industrial production.
- 相关文献
