Journal of Pure and Applied MicrobiologyVol. 8 No. 2

Optimization of Medium Composition for Antibacterial Substance Production by Aspergillus niger xj using Response Surface Methodology

Zhu Li1, Song Liu1, Yuan Song2, Wu-Juan Liu1, Xue Chen3, Qiang Wang1, Yong-Yi Ge1, Miao-Xiao Shi4 and Yi Jin5

1College of Life Sciences, Guizhou University, Guiyang 550025, China. 2School of Marine Science and Technology in Harbin Institute of Technology at Weihai, Weihai 264200, China. 3Bijie Tobacco Company of Guizhou Province, Bijie 551700, China. 4College of Anshun, Guiyang 550005, China. 5College of Mathematics and Information Technology, Guiyang University, Guiyang 550005, China.

Received on 11 June 2013 and accepted on 21 August 2013

 

ABSTRACT

To investigate the optimal medium composition for antibacterial substance production by Aspergillus niger xj in liquid-state fermentation (LSF). The disc diffusion method was used to assay the production. Statistical methodologies, including the Plackett-Burman design (PBD) and the central composite design (CCD), were employed to investigate the individual crucial component of the medium that significantly affected the production. The optimum values of the critical components for the maximum antibacterial substance production were obtained as follows: x1(MgSO4)=-0.3417 (0.2982 g/L), x2(Tween-80)=-0.28878 (0.242245 ml/L) and the predicted diameter of the inhibitory zone value was 27.39847 mm. Using the optimized condition, the diameter of inhibitory zone reached 27.74?3.07 mm. By using PBD and CCD, we determined the optimal composition for antibacterial substance production by Aspergillus niger xj in LSF.

Keywords : Antibacterial substance, Optimization of medium composition, Plackett-Burman design (PBD), Response surface methodology (RSM), Aspergillus niger xj.