Optimization of medium composition for enhanced biomass production of probiotic bacteria using response surface methodology
摘要
This study focused on optimizing the medium composition and cultivation conditions to boost the biomass production of Fructobacillus fructosus through statistical methods. The one-factor-at-a-time (OFAT) method was employed to screen carbon sources (dextrose, sucrose, fructose, starch, and lactose) and nitrogen sources (peptone, yeast extract, beef extract and their combinations, corn steep liquor, and ammonium chloride). Based on the OFAT results, four key factors were selected for the Response Surface Methodology (RSM) to determine their significant impact on biomass yield. Fructose, yeast extract, ammonium chloride, and potassium phosphate monobasic were identified as critical factors and subjected to response surface methodology using the Central Composite Design (CCD) method of analysis. The optimal medium composition obtained through RSM consisted of 22.5 g/L fructose, 8 g/L yeast extract, 2.5 g/L KH2PO4, and 2.5 g/L ammonium chloride, and the optimized physical parameters included a temperature of 37.5 °C, pH 4.5, an incubation period of 36 h, and an inoculum size of 12.5% (v/v). Under these optimized conditions, the biomass yield of F. fructosus reached an absorbance of 2.295 at 600 nm with a CFU count of 6.711 log CFU/mL, compared to the unoptimized medium with an absorbance of 1.550 at 600 nm and 5.324 CFU/mL, with a 1.48-fold increase when compared with the native MRS medium. The highest biomass yield was at 37.5 °C, pH 4.5, an incubation time of 36 h, and an inoculum size of 12.5 (%v/v). In conclusion, the mass production of F. fructosus was significantly enhanced, yielding higher biomass than in the standard MRS medium, highlighting its potential for scalable industrial applications in probiotic and functional food development.