Optimization and Preliminary Application of High Density Fermentation Conditions of Haemophilus parasuis

The effects of carbon, nitrogen, serum and coenzyme on culture of Haemophilus parasuis were investigated by single factor test, and on the basis of single factor test, the orthogonal design of four factors and three levels was employed to test the concentrations of sugar, yeast powder, ammonium sulfate and horse serum.The results showed that the optimized concentrations were that sucrose was 2 g/L, yeast powder was 2 g/L, ammonium sulfate was 2 g/L, and horse serum was 5%. Comparing the impact of different supplement methods on Haemophilus parasuis fermentation in 10 L fermentor, a good fermentation result was obtained when the residual sugar concentration was maintained at 1 g/L by supplementing constant sugar.The result showed that bacterial density and the number of viable bacteria were 16.8 and 3.6×10⁹ CFU/mL,respectively.