Optimization of Medium Composition for Biomass Production of Lactobacillus plantarum 200655 Using Response Surface Methodology

This study aimed to optimize medium composition and culture conditions for enhancing the biomass of Lactobacillus plantarum 200655 using statistical methods. The one-factor-at-a-time (OFAT) method was used to screen the six carbon sources (glucose, sucrose, maltose, fructose, lactose, and galactose) and six nitrogen sources (peptone, tryptone, soytone, yeast extract, beef extract, and malt extract). Based on the OFAT results, six factors were selected for the PlackettBurman design (PBD) to evaluate whether the variables had significant effects on the biomass. Maltose, yeast extract, and soytone were assessed as critical factors and therefore applied to response surface methodology (RSM). The optimal medium composition by RSM was composed of 31.29 g/l maltose, 30.27 g/l yeast extract, 39.43 g/l soytone, 5 g/ l sodium acetate, 2 g/l K2HPO4, 1 g/l Tween 80, 0.1 g/l MgSO4 center dot 7H(2)O, and 0.05 g/l MnSO4 center dot H2O, and the maximum biomass was predicted to be 3.951 g/l. Under the optimized medium, the biomass of L. plantarum 200655 was 3.845 g/l, which was similar to the predicted value and 1.58-fold higher than that of the unoptimized medium (2.429 g/l). Furthermore, the biomass increased to 4.505 g/l under optimized cultivation conditions. For lab-scale bioreactor validation, batch fermentation was conducted with a 5-L bioreactor containing 3.5 L of optimized medium. As a result, the highest yield of biomass (5.866 g/l) was obtained after 18 h of incubation at 30 degrees C, pH 6.5, and 200 rpm. In conclusion, mass production by L. plantarum 200655 could be enhanced to obtain higher yields than that in MRS medium

Automated summary

Medium composition and culture conditions for enhancing the biomass of Lactobacillus plantarum 200655 were optimized using statistical methods, resulting in a 1.58-fold increase in biomass compared to unoptimized medium. Batch fermentation in a lab-scale bioreactor further increased biomass yield to 5.866 g/l under optimized conditions.