Optimization Of Fermentation Conditions Of Plantaricin Produced By Lactobacillus Plantarum LPC718

Because of the advantages of safe, non-toxic, efficient and not easy to produce pathogen resistance, bacteriocins from Lactobacillus plantarum have been widely applied in food preservative, medicine industry and agriculture and so on. Plantaricin LPC718was steady in acid conditions and had good thermal stability; the inhibition spectrum was very wide, so it had a certain research value. To improve the production of plantaricin, the fermentation conditions of Plantaricin LPC718were optimized with statistical software in this paper.The positive coupled response was studied between the growth of strain LPC718and the production of Plantaricin LPC718. The exponential phase began after4-6h, the stationary phase kept from28to32h; the values of pH significantly decreased after4h and maintain about3.7after30h fermentation. The curve of antibacterial activity showed similar trend with the curve of the growth of strain LPC718. Plantaricin LPC718can be detected at4h; it obviously slowly increased after26h and decreased in the late stationary phase.The fermentation conditions of Plantaricin LPC718were studied, including fermentation temperature, initial pH, inoculation volume, seed age and culture method. The optimum fermentation conditions were as follows:seed age of14h,4%inoculation volume, stationary culture, initial pH of7.5, at36℃. Among these, pH and temperature had more significant effects than others.After single-factor experiment, the level of component was optimized with response surface method. The optimal carbon source and nitrogen source were sucrose and poly-peptone. Meanwhile, Tween80was the optimal stimulator substance. Sucrose, beef extract and MgSO4.7H2O were identified to have significant effects on Plantaricin LPC718biosynthesis by a Plackett-Burman design. After Box-Benhnken design, Response Surface Methodology was applied for the optimization of Plantaricin LPC718production, the optimum medium composition was obtained as follow (g/L):sucrose41.16, yeast extract5.0, poly-peptone10, beef extract20.49, MgSO4.7H2O1.13, K2HPO42, tri-ammonium citrate5, CH3COONa5, MnSO40.25, Tween805ml.