Optimization of medium composition of Y44 using PlackettBurman and Box-Behnken designs.

The biomass of strains depends on the culture media and culture conditions. The purpose of this study was to optimize the culture medium composition and culture conditions of Y44 to improve its biomass. The utilization of different carbon sources and nitrogen sources by Y44 was assessed by single factor experiment to screen out the economical carbon and nitrogen sources for Y44 growth. Through optimization experiments, the optimized culture medium for Y44 growth consists of soybean peptone 44.1 g/L, yeast extract 22.1 g/L, sucrose 35.6 g/L, hydrogen diamine citrate 2 g/L, anhydrous sodium acetate 8.5 g/L, dipotassium hydrogen phosphate 4 g/L, Tween-80 2 mL/L, manganese sulfate 0.25 g/L, and magnesium sulfate 0.58 g/L, and the initial pH 6.7. The concentration of viable bacteria cells of Y44 culturing in the optimized medium at 37 °C for 16 h was up to 3.363 × 10 CFU/mL, as 6.11 times higher than that in the MRS medium.