Abstract: Response surface methodology (RSM) was used to optimize the medium components of B.breve A04. In the firststep of the optimization, a factional factorial design was used to evaluate the effects of nine factors. The results showed that threefactors, including glucose, yeast extract and initial pH had significant effects on bacteria dry weight. Secondly, the path ofsteepest ascent was used to gain the optimal region of the three factors. At last, the concentrations were optimized using CCRD(Central Composite Rotable Design) and RSM analysis. As a result, the contents were obtained as follows: (/L): glucose5.194g,yeast extract2.829g, FOS 2g, tomato juice50ml, liver infusion 5g, Tween80 1ml, cystein-HCl 0.3g, and pH6.463. Final dryweight of biomass was obtained as 4.462g/L, 1.43 higher than before 3.16 g/L.

Key words:  , Bifidobacterium breve A04； medium； optimization； response surface methodology；