African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5210

Full Length Research Paper

Medium optimization for the production of a metagenome-derived β-galactosidase by Pichia pastoris using response surface methodology

Chang-Jie Li1, Xia Zhang1, Li-Ping Zhang1, An Wang1, Run-Qian Mao2 and Gang Li1*  
1The Key Laboratory of Gene Engineering of Ministry of Education, Sun Yat-sen University, Guangzhou, 510275, People’s Republic of China. 2Guangdong Entomological Institute, Guangzhou 510260, People’s Republic of China
Email: [email protected]

  •  Accepted: 15 March 2013
  •  Published: 26 March 2013


To investigate the optimal medium for the production of a metagenome-derived β-galactosidase (ZQ114) by Pichia pastorisi, Plackett and Burman design was applied to screen the significance of eight medium compositions, and three factors (methanol, sorbitol and MgSO4.7H2O) were found to have significant effect on the production of ZQ114. Then, the steepest ascent method was further used to determine their optimal levels, and Box-Behnken design and response surface methodology were eventually adopted to derive a statistical model for optimizing the medium. The experimental results indicate that the optimum of three main factors was 10.43 g/L (methanol), 33.98 g/L (sorbitol), and 0.52 g/L (MgSO4.7H2O), respectively. The highest yield of ZQ114 using the optimal medium reached up to 14.94 U/mL with lactose as substrate, which was 2.57 times higher than that unoptimized. Also, the experimental data of 14.94 U/mL is basiclly accordant with the predicted value (14.68 U/mL).


Key words: β-Galactosidase, enzyme production, medium optimization, response surface methodology.