Journal of Pure and Applied MicrobiologyVol. 7 No. 2

Optimization of Fermentation Medium for Cell Yield of Recombinant Pichia pastoris during Growth Stage using Response Surface Methodology

Zi F. Shang1,2, Dai D. Fan1,2*, Jian J. Deng1,2, Pei Ma1,2, Xiaoxuan Ma1,2 and Yu Mi1,2*

1Shaanxi Key Laboratory of Degradable Biomedical Materials, Northwest University, Taibai North Road 229 Xi’an, Shaanxi - 710 069, China. 2Shaanxi R&D Center of Biomaterials and Fermentation Engineering, School of Chemical Engineering, Northwest University, Xi’an - 710 069, China.

Received on 30 March 2013 and accepted on 22 May 2013

 

ABSTRACT

In order to improve the cell yeild of recombinant Pichia pastoris during fermentation of glycerol growth stage, the Placket-Burman and Box-Behnken design were applied to optimize the fermentation medium (BMGY). Three variables (yeast extra, peptone and glycerol) which were proved to have significant effects on dry cell weight (DCW) were selected from six variables by Placket-Burman design. Through Box-Behnken design Regression coefficients analysis, a secondary degree polynomial equation was established, and the optimum levels of the three variables were as following: yeast extra 1.13%, peptone 1.61% and glycerol 0.86%. From the 3D response surface plots and 2D contour plots created by the Box-Behnken design, we can also observed the interaction between yeast extra and peptone or yeast extra and glycerol are significant. An average 4.41 g/l DCW after 12 h cultivation in the optimized BMGY media could be attained by the validation experiments, which was 20.6% higher than the formal yield of 3.50 g/l.

Keywords : Fermentation, Optimization, Placket-Burman design, Response surface methodology.