Optimization of medium composition for production of lacticin LLC518 by Lactococcus lactis subsp lactis LLC518 using response surface methodology

Response surface methodology (RSM) was applied for the optimization of lacticin LLC518 production, which was produced by Lactococcus lactis subsp. locus LLC518. Tryptone, KH2PO4 and MgSO4 had signicant effects on lacticin LLC518 biosynthesis by a Plackett-Burman design (PBD). After steepest ascent design (SAD) and central composite design (CCD), the optimum medium compositions were obtained as follows (g/l): sucrose 20, yeast extract 5, tryptone 8.18, beef extract 10, MgSO4 center dot 7H(2)O 0.82, K2HPO4 2.8, (NH4)(2)HC6H5O7 5.0, CH3COONa 5.0, MnSO4 0.25 and Tween 80 5 ml. An 86.3% increase in bacteriocin production (180.13 IU/ml) was achieved under this condition compared within unoptimized medium (96.72 IU/ml). Under these optimized conditions, the production of Lacticin LLC518 began at 4 h, peaked at 14 h.