Application of a novel cavern volume controlled culture model to microbial hyaluronic acid production by batch culture of Streptococcus zooepidemicus

Abstract

With the unique physio-chemical and biological properties, hyaluronic acid (HA) finds a wide range of applications in biomedical, cosmetic and healthcare fields. The microbial HA production is limited by poor mixing performance and low oxygen mass transfer rate. In this work, a novel cavern volume controlled culture model was proposed and applied to microbial HA production by batch culture of Streptococcus zooepidemicus. In the cavern model-controlled culture process, the complete mixing was achieved via the dynamic control of agitation speed in the range from 50 rpm to 470 rpm, and HA yield increased from 5.5 ± 0.1 g/L of the control to 6.2 ± 0.1 g/L. There was not significant influence of the model-controlled culture on the molecular weight of HA compared with the control, in which the agitation speed was kept at 294 rpm. With better mixing performance and improved oxygen mass transfer efficiency, the cavern volume controlled culture model may be helpful for the production of the other microbial biopolymers like xanthan gum, curdlan and poly(glutamic acid).