Optimization of fermentation medium of Bacillus amyloliquefaciens ZJHD-06 by response surface methodology

The fermentation medium of Bacillus amyloliquefacien ZJHD- 06 isolated from intestine of Epinephelus areolatus was optimized for a bacteriocin-like substance ( BLS) production.Bacteriostatic circle diameter was used as evaluation index against L.monocytogenes ATCC 35152.Firstly, the notable factors were screened by Plackett- Burman experiment design.Then, the path of steepest ascent was undertaken to approach the optimal region of the significant factors.Finally, Box-Behnken design was adopted to identify optimal proportion.The results showed the optimal proportions were glucose 4.80%, peptone 0.47%, yeast extract 0.44%, NaCl 1.0%, K 2 HPO 4 0.01% and MgSO 4 ·7H 2 O 0.03%. The bacteriostatic circle diameter of the fermentation supernatant was increased by 27.8% using the optimal proportions.