Optimization of the production of Weissella confusa MBF8-1 lysate in plant-based media by using response surface methodology

Aims: Bacterial lysate has been reported to possess many health-care-related benefits. This study aimed to determine the optimum conditions for producing Weissella confusa MBF8-1 lysate in two plant-based modified De Man, Rogosa, and Sharpe (MRS) media using the response surface methodology (RSM). In this study, we applied several condition factors and compared them to standard MRS media. Methodology and results: Weissella confusa MBF8-1 was grown in two modified MRS media, which are MRS Vegitone and soy peptone modified-MRS. The optimized fermentation condition factors such as nitrogen sources (i.e., soy peptone, proteose peptone), dextrose concentrations, and fermentation time were measured, and the responses, such as bacteriocin-like inhibitory substance (BLIS) activity and lysate pH were observed. RSM results showed the diameter of BLIS activity-inhibition zone and pH decreases of the lysate produced in MRS Vegitone containing 1.50% dextrose, 0.75% proteose peptone for 11.75 h fermentation and in soy peptone modified-MRS containing 2.05% dextrose, 1.05% soy peptone for 7.53 h fermentation, i.e., 7.41 mm at 7.36, and 7.80 mm at 7.30, respectively. Whereas, lysate produced in standard MRS medium containing 2% dextrose, 1% peptone for 8 h fermentation showed 7.85 mm diameter of BLIS activity-inhibition zone at pH 7.26. W. confusa MBF8-1 lysate showed slightly lower pH, but higher BLIS activity when grown in standard MRS media compared to those of the two modified MRS media. Conclusion, significance and impact of study: The data obtained provide the optimum condition of W. confusa MBF8-1 lysate production in plant-based media. The pH and BLIS activity possessed by W. confusa MBF8-1 lysate produced in soy peptone modified-MRS showed a more similar result as the standard one than the other modified one. Thus, the soy peptone modified-MRS is recommended as a plant-based alternative medium replacing standard MRS.