Optimization of an Industrial Medium and Culture Conditions for Probiotic Weissella cibaria JW15 Biomass Using the Plackett-Burman Design and Response Surface Methodology

The objective of this study was to optimize industrial- grade media for improving the biomass production of Weissella cibaria JW15 (JW15) using a statistical approach. Eleven variables comprising three carbon sources (glucose, fructose, and sucrose), three nitrogen sources (protease peptone, yeast extract, and soy peptone), and five mineral sources (K2HPO4, potassium citrate, L-cysteine phosphate, MgSO4, and MnSO4) were screened by using the Plackett-Burman design. Consequently, glucose, sucrose, and soy peptone were used as significant variables in response surface methodology (RSM). The composition of the optimal medium (OM) was 22.35 g/l glucose, 15.57 g/l sucrose, and 10.05 g/l soy peptone, 2.0 g/l K2HPO4, 5.0 g/l sodium acetate, 0.1 g/l MgSO4 center dot 7H(2)O, 0.05 g/l MnSO4 center dot H2O, and 1.0 g/l Tween 80. The OM significantly improved the biomass production of JW15 over an established commercial medium (MRS). After fermenting OM, the dry cell weight of JW15 was 4.89 g/l, which was comparable to the predicted value (4.77 g/l), and 1.67 times higher than that of the MRS medium (3.02 g/l). Correspondingly, JW15 showed a rapid and increased production of lactic and acetic acid in the OM. To perform a scale-up validation, batch fermentation was executed in a 5-l bioreactor at 37 degrees C with or without a pH control at 6.0 +/- 0.1. The biomass production of JW15 significantly improved (1.98 times higher) under the pH control, and the cost of OM was reduced by two- thirds compared to that in the MRS medium. In conclusion, OM may be utilized for mass producing JW15 for industrial use.

Automated summary

This study optimized an industrial-grade media to improve the biomass production of Weissella cibaria JW15. The significant variables, glucose, sucrose, and soy peptone, were determined using response surface methodology. The optimal medium composition resulted in a significant increase in JW15 biomass production and reduced cost.