Study on the fermentation process of Haemophilus parasuis type 4 H25, type 5 H45, and type12 H31 strains
The aim of this study was to determine the optimal fermentation culture conditions for Haemophilus parasuis type4 H25 strain,type5 H45 strain,type12 H31 strain. Preliminary study on liquid fermentation culture was performed under shaking bottle and fermentation tank conditions. Under shake flask cultivation conditions, the growth curve, inoculation amount, cultivation temperature, serum and NAD content, were determined to set the foundation for the subsequent control parameters of fermentation tank. On a 50 L fermentation tank, fermentation experiments were conducted by combining control parameters such as temperature, pH, dissolved oxy-gen, stirring speed, pressure, and feeding strategy. The optimal fermentation conditions were determined through analysis of live bacte-rial count and bacterial density (OD600nm). Further scale up to 100 L and 1000 L fermentation tanks to verify stability. The optimal shake flask culture conditions were preliminarily determined by drawing growth curves. The results showed that the optimal harvest time of type4 H25 strain, type5 H45 strain, and type12 H31 strain were one hour after the bacterial density (OD 600nm) reached stationary phase. The optimal inoculation amount was 1％～3％, the optimal incubation temperature was 36～38 ℃, the optimal serum concentra-tion was 8％～10％, and the optimal NAD concentration was 8～16 μg/mL. Under the fermenter culture conditions, the optimal fermen-tation conditions for Haemophilus parasuis type4 H25 strain, type5 H45 strain, type12 H31 strain were:temperature 36～38 ℃, pH7.2-7.4, DO10％～20％, stirring speed 100～300 r/min, tank pressure 0.02 Mpa, feeding strategy was to add 20％ glucose solution, and maintain glucose concentration at 0.8～1.2 g/L. All three strains can reach a viable bacterial count of over 1010CFU/mL, meeting the re-quirements of regulations and industrial production.
万方数据
维普
