Screening Of Medium Compounds Using A Two-Level Factorial Design For Saccharomyces Boulardii

Even if the probiotic effect of Saccharomyces boulardii is has been reported, this yeast is rarely used in medium composition. Based on single factor experiment, two-level factorial design was employed to evaluate the effect of carbon sources (sucrose, glucose), nitrogen sources (soy peptone, beef extract, yeast extract, calf serum, malt extract) and salts (K2HPO4, KH2PO4, MgSO4, Na2HPO4, NaH2PO4, CaCl2, sodium citrate, sodium glutamate) on the growth of S. boulardii. At the same time, the optical density (OD) in the medium was measured at 560 nm after 36 h of incubation. The result of two-level factorial design experiment showed that calf serum (p = 0.0214) and sodium citrate (p = 0.0045) are the significant growth factors of S. boulardii, sucrose (p = 0.0861) and malt extract (p = 0.0763) are important factors. In addition, sucrose and sodium citrate showed positive effect on the growth of S. boulardii. However, calf serum and malt extract showed negative effect on the growth. And we determined that the optimum medium composition for S. boulardii was as follow: 37.5 g.L-1 sucrose, 6 g.L-1 calf serum, 6 g.L-1 malt extract, 5 g.L-1 sodium citrate.