Abstract: To increase the yield of bacteriocin produced by Lactobacillus plantarum P158, the medium and culture conditions for this strain were optimized using one-factor-at-a-time and orthogonal array design methods. The bacteriostatic activity of bacteriocin against Micrococcus luteus and Pseudomonas aeruginosa and pH were used as response variables. Results showed that MRS was the most suitable for bacteriocin production among five culture media for lactic acid bacteria.The optimal culture conditions were obtained as follows: inoculum amount, 3% (V/V); initial pH, 6.0; and static culture at 34 ℃ for 42 h; the optimum medium was composed of glucose 2 g/100 mL, yeast extract 2 g/100 mL, soy peptone 1.5 g/100 mL, MgSO4 0.058 g/100 mL, MnSO4 0.025 g/100 mL, FeSO4 0.02 g/100 mL, Tween 80 0.08 g/100 mL, sodium acetate 0.5 g/100 mL, and K2HPO4 0.2 g/100 mL. Under these conditions, bacteriocin titer was 1 145 IU/mL, which was 216% higher than that (362 IU/mL) before optimization.

Key words: Lactobacillus plantarum, bacteriocin, medium, culture conditions