Full Length Research Paper

Optimization of critical medium components for higher phycocyanin holo-α subunit production in Escherichia coli using statistical approach

Wei-hong Lu^{1, 2}, Jian-rong Li¹* and Ping Yu¹

¹College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang Province, 310035, China.

²Medical School, Jinhua College of Profession and Technology, Jinhua, Zhejiang Province, 321000, China.

Corresponding author. E-mail: 168luweihong@163.com or lijianrong@zjgsu.edu.cn  Tel: +86-571-88056656.

Accepted 24 June, 2009

To improve phycocyanin holo-α subunit (cpcA) production from Escherichia coli BL21 (DE3) cells, culture medium was screened and optimized using the statistical experimental designs of Plackett-Burman and response surface methodology. In the first step, one-factor-at-a-time method was used to evaluate the effect of carbon sources and nitrogen sources on the yield of cpcA. A two-level Plackett-Burman design was then adopted to select the most important nutrients influencing the cpcA production, which showed that beef extract, KH₂PO₄ and K₂HPO₄·3H₂O were the most significant ingredients (P< 0.05). Finally, response surface Box-Behnken design was employed to develop a mathematical model to identify the optimum concentrations of the key components for higher cpcA production, which revealed these as follows: beef extract (2.22%, w/v), KH₂PO₄ (0.52%, w/v), K₂HPO₄·3H₂O (0.94%, w/v). The high correlation between the predicted and observed values indicated the validity of the model. CpcA yield increased significantly with optimized medium (47.62 mg/L) when compared with original medium (2.72 mg/L).

Key words: Phycocyanin holo-α subunit, Plackett-Burman design, optimization, response surface methodology.