Comparative study on the influence of dissolved oxygen control approaches on the microbial hyaluronic acid production of Streptococcus zooepidemicus.

Three different dissolved oxygen (DO) control approaches were proposed to improve hyaluronic acid (HA) production: a three-stage agitation speed control approach, a two-stage DO control approach, and an oxygen vector perfluorodecalin (PFC) applied approach. In the three-stage agitation speed control approach, agitation speed was 200 rpm during 0-8 h, 400 rpm during 8-12 h, and 600 rpm during 12-20 h. In the two-stage DO control strategy, DO was controlled at above 10% during 0-8 h and at 5% during 8-20 h. In the PFC applied approach, PFC (3% v/v) was added at 8 h. HA production reached 5.5 g/L in the three-stage agitation speed control culture model, and 6.3 g/L in two-stage DO control culture model, and 6.6 g/L in the PFC applied culture model. Compared with the other two DO control approaches, the PFC applied approach had a lower shear stress and thus a higher HA production was achieved.