Fermentation process development for hyaluronic acid production by Streptococcus zooepidemicus ATCC 39920

The development of a fermentation strategy for hyaluronic acid (HA) production by Streptococcus zooepidemicus ATCC 39920 has been explored. The specific HA productivity (Y-P/X) was affected by the medium carbon-to-nitrogen (C/N) ratio rather than the specific growth rate of cells. Accordingly, HA fermentation should be performed in a balanced medium with an optimum C/N ratio of 2: 1 in a batch culture. To improve the performance of the batch culture, the operation conditions for the fill-and-draw culture were investigated. It was found that the timing of medium exchange is critical for successfully performing fill-and-draw operations. Since streptococcal cells at the stationary phase might lose the capacity of HA synthesis, the displacement of the medium in a fill-and-draw culture should be started at the late exponential growth phase.